Air conditioner

ABSTRACT

In an air conditioner that uses a refrigerant mixture containing at least 1,2-difluoroethylene, high efficiency is achieved. The motor rotation rate of a compressor ( 100 ) can be changed in accordance with an air conditioning load, and thus a high annual performance factor (APF) can be achieved. In addition, an electrolytic capacitor is not required on an output side of a rectifier circuit ( 21 ), and thus an increase in the size and cost of the circuit is suppressed.

TECHNICAL FIELD

The present invention relates to an air conditioner that uses refrigerant with a low global warming potential (GWP).

BACKGROUND ART

In recent years, use of refrigerant with a low GWP (hereinafter referred to as low-GWP refrigerant) in air conditioners has been considered from the viewpoint of environmental protection. A dominant example of low-GWP refrigerant is a refrigerant mixture containing 1,2-difluoroethylene.

SUMMARY OF THE INVENTION Technical Problem

However, the related art giving consideration from the aspect of increasing the efficiency of air conditioners using the foregoing refrigerant is rarely found. For example, in the case of applying the foregoing refrigerant to the air conditioner disclosed in PTL 1 (Japanese Unexamined Patent Application Publication No. 2013-124848), there is an issue of how to achieve high efficiency.

Solution to Problem

An air conditioner according to a first aspect includes a compressor that compresses a refrigerant mixture containing at least 1,2-difluoroethylene, a motor that drives the compressor, and a power conversion device. The power conversion device is connected between an alternating-current (AC) power source and the motor, has a switching element, and controls the switching element such that an output of the motor becomes a target value.

In the air conditioner that uses a refrigerant mixture containing at least 1,2-difluoroethylene, the motor rotation rate of the compressor can b e changed in accordance with an air conditioning load, and thus a high annual performance factor (APF) can be achieved.

An air conditioner according to a second aspect is the air conditioner according to the first aspect, in which the power conversion device includes a rectifier circuit and a capacitor. The rectifier circuit rectifies an AC voltage of the AC power source. The capacitor is connected in parallel to an output side of the rectifier circuit and smooths voltage variation caused by switching in the power conversion device.

In this air conditioner, an electrolytic capacitor is not required on the output side of the rectifier circuit, and thus an increase in the size and cost of the circuit is suppressed.

An air conditioner according to a third aspect is the air conditioner according to the first aspect or the second aspect, in which the AC power source is a single-phase power source.

An air conditioner according to a fourth aspect is the air conditioner according to the first aspect or the second aspect, in which the AC power source is a three-phase power source.

An air conditioner according to a fifth aspect is the air conditioner according to the first aspect, in which the power conversion device is an indirect matrix converter including a converter and an inverter. The converter converts an AC voltage of the AC power source into a direct-current (DC) voltage. The inverter converts the DC voltage into an AC voltage and supplies the AC voltage to the motor.

This air conditioner is highly efficient and does not require an electrolytic capacitor on the output side of the rectifier circuit, and thus an increase in the size and cost of the circuit is suppressed.

An air conditioner according to a sixth aspect is the air conditioner according to the first aspect, in which the power conversion device is a matrix converter that directly converts an AC voltage of the AC power source into an AC voltage having a predetermined frequency and supplies the AC voltage having the predetermined frequency to the motor.

This air conditioner is highly efficient and does not require an electrolytic capacitor on the output side of the rectifier circuit, and thus an increase in the size and cost of the circuit is suppressed.

An air conditioner according to a seventh aspect is the air conditioner according to the first aspect, in which the compressor is any one of a scroll compressor, a rotary compressor, a turbo compressor, and a screw compressor.

An air conditioner according to an eighth aspect is the air conditioner according to any one of the first aspect to the seventh aspect, in which the motor is a permanent magnet synchronous motor having a rotor including a permanent magnet.

An air conditioner according to a ninth aspect is the air conditioner according to any of the first through eighth aspects, wherein the refrigerant comprises trans-1,2-difluoroethylene (HFO-1132(E)), difluoromethane (R32), and 2,3,3,3-tetrafluoro-1-propene (R1234yf),

wherein

when the mass % of HFO-1132(E), R32, and R1234yf based on their sum in the refrigerant is respectively represented by x, y, and z, coordinates (x,y,z) in a ternary composition diagram in which the sum of HFO-1132(E), R32, and R1234yf is 100 mass % are within the range of a figure surrounded by line segments IJ, JN, NE, and EI that connect the following 4 points:

point I (72.0, 0.0, 28.0), point J (48.5, 18.3, 33.2), point N (27.7, 18.2, 54.1), and point E (58.3, 0.0, 41.7), or on these line segments (excluding the points on the line segment EI;

the line segment IJ is represented by coordinates (0.0236y²−1.7616y+72.0, y, −0.0236y²+0.7616y+28.0);

the line segment NE is represented by coordinates (0.012y²−1.9003y+58.3, y, −0.012y²+0.9003y+41.7); and

the line segments JN and EI are straight lines.

In this air conditioner, the motor rotation rate of the compressor can be changed in accordance with an air conditioning load, and thus a high annual performance factor (AFP) can also be achieved when a refrigerant having a sufficiently low GWP, a refrigeration capacity (may also be referred to as a cooling capacity or a capacity) equal to those of R410A and classified with lower flammability (Class 2L) in the standard of The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) is used.

An air conditioner according to a tenth aspect is the air conditioner according to any of the first through eighth aspects, wherein the refrigerant comprises HFO-1132(E), R32, and R1234yf,

wherein

when the mass % of HFO-1132(E), R32, and R1234yf based on their sum in the refrigerant is respectively represented by x, y, and z, coordinates (x,y,z) in a ternary composition diagram in which the sum of HFO-1132(E), R32, and R1234yf is 100 mass % are within the range of a figure surrounded by line segments MM′, M′N, NV, VG, and GM that connect the following 5 points:

point M (52.6, 0.0, 47.4), point M′ (39.2, 5.0, 55.8), point N (27.7, 18.2, 54.1), point V (11.0, 18.1, 70.9), and point G (39.6, 0.0, 60.4), or on these line segments (excluding the points on the line segment GM);

the line segment MM′ is represented by coordinates (0.132y²−3.34y+52.6, y, −0.132y²+2.34y+47.4);

the line segment M′N is represented by coordinates (0.0596y²−2.2541y+48.98, y, −0.0596y²+1.2541y+51.02);

the line segment VG is represented by coordinates (0.0123y²−1.8033y+39.6, y, −0.0123y²+0.8033y+60.4); and

the line segments NV and GM are straight lines.

In this air conditioner, the motor rotation rate of the compressor can be changed in accordance with an air conditioning load, and thus a high annual performance factor (AFP) can also be achieved when a refrigerant having a sufficiently low GWP, a refrigeration capacity (may also be referred to as a cooling capacity or a capacity) equal to those of R410A and classified with lower flammability (Class 2L) in the standard of The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) is used.

An air conditioner according to a eleventh aspect is the air conditioner according to any of the first through eighth aspects, wherein the refrigerant comprises HFO-1132(E), R32, and R1234yf,

wherein

when the mass % of HFO-1132(E), R32, and R1234yf based on their sum in the refrigerant is respectively represented by x, y and z, coordinates (x,y,z) in a ternary composition diagram in which the sum of HFO-1132(E), R32, and R1234yf is 100 mass % are within the range of a figure surrounded by line segments ON, NU, and UO that connect the following 3 points:

point O (22.6, 36.8, 40.6), point N (27.7, 18.2, 54.1), and point U (3.9, 36.7, 59.4), or on these line segments;

the line segment ON is represented by coordinates (0.0072y²−0.6701y+37.512, y, −0.0072y²−0.3299y+62.488);

the line segment NU is represented by coordinates (0.0083y²−1.7403y+56.635, y, −0.0083y²+0.7403y+43.365); and

the line segment UO is a straight line.

In this air conditioner, the motor rotation rate of the compressor can be changed in accordance with an air conditioning load, and thus a high annual performance factor (AFP) can also be achieved when a refrigerant having a sufficiently low GWP, a refrigeration capacity (may also be referred to as a cooling capacity or a capacity) equal to those of R410A and classified with lower flammability (Class 2L) in the standard of The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) is used.

An air conditioner according to a twelfth aspect is the air conditioner according to any of the first through eighth aspects, wherein the refrigerant comprises HFO-1132(E), R32, and R1234yf,

wherein

when the mass % of HFO-1132(E), R32, and R1234yf based on their sum in the refrigerant is respectively represented by x, y, and z, coordinates (x,y,z) in a ternary composition diagram in which the sum of HFO-1132(E), R32, and R1234yf is 100 mass % are within the range of a figure surrounded by line segments QR, RT, TL, LK, and KQ that connect the following 5 points:

point Q (44.6, 23.0, 32.4), point R (25.5, 36.8, 37.7), point T (8.6, 51.6, 39.8), point L (28.9, 51.7, 19.4), and point K (35.6, 36.8, 27.6), or on these line segments;

the line segment QR is represented by coordinates (0.0099y²−1.975y+84.765, y, −0.0099y²+0.975y+15.235);

the line segment RT is represented by coordinates (0.0082y²−1.8683y+83.126, y, −0.0082y²+0.8683y+16.874);

the line segment LK is represented by coordinates (0.0049y²−0.8842y+61.488, y, −0.0049y²−0.1158y+38.512);

the line segment KQ is represented by coordinates (0.0095y²−1.2222y+67.676, y, −0.0095y²+0.2222y+32.324); and

the line segment TL is a straight line.

In this air conditioner, the motor rotation rate of the compressor can be changed in accordance with an air conditioning load, and thus a high annual performance factor (AFP) can also be achieved when a refrigerant having a sufficiently low GWP, a refrigeration capacity (may also be referred to as a cooling capacity or a capacity) equal to those of R410A and classified with lower flammability (Class 2L) in the standard of The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) is used.

An air conditioner according to a thirteenth aspect is the air conditioner according to any of the first through eighth aspects, wherein the refrigerant comprises HFO-1132(E), R32, and R1234yf,

wherein

when the mass % of HFO-1132(E), R32, and R1234yf based on their sum in the refrigerant is respectively represented by x, y, and z, coordinates (x,y,z) in a ternary composition diagram in which the sum of HFO-1132(E), R32, and R1234yf is 100 mass % are within the range of a figure surrounded by line segments PS, ST, and TP that connect the following 3 points:

point P (20.5, 51.7, 27.8), point S (21.9, 39.7, 38.4), and point T (8.6, 51.6, 39.8), or on these line segments;

the line segment PS is represented by coordinates (0.0064y²−0.7103y+40.1, y, −0.0064y²−0.2897y+59.9);

the line segment ST is represented by coordinates (0.0082y²−1.8683y+83.126, y, −0.0082y²+0.8683y+16.874); and

the line segment TP is a straight line.

In this air conditioner, the motor rotation rate of the compressor can be changed in accordance with an air conditioning load, and thus a high annual performance factor (AFP) can also be achieved when a refrigerant having a sufficiently low GWP, a refrigeration capacity (may also be referred to as a cooling capacity or a capacity) equal to those of R410A and classified with lower flammability (Class 2L) in the standard of The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) is used.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of an instrument used for a flammability test.

FIG. 2 is a view showing points A to C, E, G, and I to W; and line segments that connect points A to C, E, G, and I to W in a ternary composition diagram in which the sum of HFO-1132(E), R32, and R1234yf is 100 mass %.

FIG. 3 is a configuration diagram of an air conditioner according to a first embodiment of the present disclosure.

FIG. 4 is a circuit block diagram of a power conversion device mounted in an air conditioner according to the first embodiment.

FIG. 5 is a circuit block diagram of a power conversion device according to a modification example of the first embodiment.

FIG. 6 is a circuit block diagram of a power conversion device mounted in an air conditioner according to a second embodiment of the present disclosure.

FIG. 7 is a circuit block diagram of a power conversion device according to a modification example of the second embodiment.

FIG. 8 is a circuit block diagram of a power conversion device mounted in an air conditioner according to a third embodiment of the present disclosure.

FIG. 9 is a circuit diagram conceptionally illustrating a bidirectional switch.

FIG. 10 is a circuit diagram illustrating an example of a current direction in a matrix converter.

FIG. 11 is a circuit diagram illustrating an example of another current direction in the matrix converter.

FIG. 12 is a circuit block diagram of a power conversion device according to a modification example of the third embodiment.

FIG. 13 is a circuit diagram of a clamp circuit.

DESCRIPTION OF EMBODIMENTS (1) Definition of Terms

In the present specification, the term “refrigerant” includes at least compounds that are specified in ISO 817 (International Organization for Standardization), and that are given a refrigerant number (ASHRAE number) representing the type of refrigerant with “R” at the beginning; and further includes refrigerants that have properties equivalent to those of such refrigerants, even though a refrigerant number is not yet given. Refrigerants are broadly divided into fluorocarbon compounds and non-fluorocarbon compounds in terms of the structure of the compounds. Fluorocarbon compounds include chlorofluorocarbons (CFC), hydrochlorofluorocarbons (HCFC), and hydrofluorocarbons (HFC). Non-fluorocarbon compounds include propane (R290), propylene (R1270), butane (R600), isobutane (R600a), carbon dioxide (R744), ammonia (R717), and the like.

In the present specification, the phrase “composition comprising a refrigerant” at least includes (1) a refrigerant itself (including a mixture of refrigerants), (2) a composition that further comprises other components and that can be mixed with at least a refrigeration oil to obtain a working fluid for a refrigerating machine, and (3) a working fluid for a refrigerating machine containing a refrigeration oil. In the present specification, of these three embodiments, the composition (2) is referred to as a “refrigerant composition” so as to distinguish it from a refrigerant itself (including a mixture of refrigerants). Further, the working fluid for a refrigerating machine (3) is referred to as a “refrigeration oil-containing working fluid” so as to distinguish it from the “refrigerant composition.”

In the present specification, when the term “alternative” is used in a context in which the first refrigerant is replaced with the second refrigerant, the first type of “alternative” means that equipment designed for operation using the first refrigerant can be operated using the second refrigerant under optimum conditions, optionally with changes of only a few parts (at least one of the following: refrigeration oil, gasket, packing, expansion valve, dryer, and other parts) and equipment adjustment. In other words, this type of alternative means that the same equipment is operated with an alternative refrigerant. Embodiments of this type of “alternative” include “drop-in alternative,” “nearly drop-in alternative,” and “retrofit,” in the order in which the extent of changes and adjustment necessary for replacing the first refrigerant with the second refrigerant is smaller.

The term “alternative” also includes a second type of “alternative,” which means that equipment designed for operation using the second refrigerant is operated for the same use as the existing use with the first refrigerant by using the second refrigerant. This type of alternative means that the same use is achieved with an alternative refrigerant.

In the present specification, the term “refrigerating machine” refers to machines in general that draw heat from an object or space to make its temperature lower than the temperature of ambient air, and maintain a low temperature. In other words, refrigerating machines refer to conversion machines that gain energy from the outside to do work, and that perform energy conversion, in order to transfer heat from where the temperature is lower to where the temperature is higher.

In the present specification, a refrigerant having a “WCF lower flammability” means that the most flammable composition (worst case of formulation for flammability: WCF) has a burning velocity of 10 cm/s or less according to the US ANSI/ASHRAE Standard 34-2013. Further, in the present specification, a refrigerant having “ASHRAE lower flammability” means that the burning velocity of WCF is 10 cm/s or less, that the most flammable fraction composition (worst case of fractionation for flammability: WCFF), which is specified by performing a leakage test during storage, shipping, or use based on ANSI/ASHRAE 34-2013 using WCF, has a burning velocity of 10 cm/s or less, and that flammability classification according to the US ANSI/ASHRAE Standard 34-2013 is determined to classified as be “Class 2L.”

In the present specification, a refrigerant having an “RCL of x % or more” means that the refrigerant has a refrigerant concentration limit (RCL), calculated in accordance with the US ANSI/ASHRAE Standard 34-2013, of x % or more. RCL refers to a concentration limit in the air in consideration of safety factors. RCL is an index for reducing the risk of acute toxicity, suffocation, and flammability in a closed space where humans are present. RCL is determined in accordance with the ASHRAE Standard. More specifically, RCL is the lowest concentration among the acute toxicity exposure limit (ATEL), the oxygen deprivation limit (ODL), and the flammable concentration limit (FCL), which are respectively calculated in accordance with sections 7.1.1, 7.1.2, and 7.1.3 of the ASHRAE Standard.

In the present specification, temperature glide refers to an absolute value of the difference between the initial temperature and the end temperature in the phase change process of a composition containing the refrigerant of the present disclosure in the heat exchanger of a refrigerant system.

(2) Refrigerant (2-1) Refrigerant Component

Any one of various refrigerants, such as refrigerant D, details of these refrigerant are to be mentioned later, can be used as the refrigerant.

(2-2) Use of Refrigerant

The refrigerant according to the present disclosure can be preferably used as a working fluid in a refrigerating machine.

The composition according to the present disclosure is suitable for use as an alternative refrigerant for HFC refrigerant such as R410A, R407C and R404 etc, or HCFC refrigerant such as R22 etc.

(3) Refrigerant Composition

The refrigerant composition according to the present disclosure comprises at least the refrigerant according to the present disclosure, and can be used for the same use as the refrigerant according to the present disclosure. Moreover, the refrigerant composition according to the present disclosure can be further mixed with at least a refrigeration oil to thereby obtain a working fluid for a refrigerating machine.

The refrigerant composition according to the present disclosure further comprises at least one other component in addition to the refrigerant according to the present disclosure. The refrigerant composition according to the present disclosure may comprise at least one of the following other components, if necessary. As described above, when the refrigerant composition according to the present disclosure is used as a working fluid in a refrigerating machine, it is generally used as a mixture with at least a refrigeration oil. Therefore, it is preferable that the refrigerant composition according to the present disclosure does not substantially comprise a refrigeration oil. Specifically, in the refrigerant composition according to the present disclosure, the content of the refrigeration oil based on the entire refrigerant composition is preferably 0 to 1 mass %, and more preferably 0 to 0.1 mass %.

(3-1) Water

The refrigerant composition according to the present disclosure may contain a small amount of water. The water content of the refrigerant composition is preferably 0.1 mass % or less based on the entire refrigerant. A small amount of water contained in the refrigerant composition stabilizes double bonds in the molecules of unsaturated fluorocarbon compounds that can be present in the refrigerant, and makes it less likely that the unsaturated fluorocarbon compounds will be oxidized, thus increasing the stability of the refrigerant composition.

(3-2) Tracer

A tracer is added to the refrigerant composition according to the present disclosure at a detectable concentration such that when the refrigerant composition has been diluted, contaminated, or undergone other changes, the tracer can trace the changes.

The refrigerant composition according to the present disclosure may comprise a single tracer, or two or more tracers.

The tracer is not limited, and can be suitably selected from commonly used tracers. Preferably, a compound that cannot be an impurity inevitably mixed in the refrigerant of the present disclosure is selected as the tracer.

Examples of tracers include hydrofluorocarbons, hydrochlorofluorocarbons, chlorofluorocarbons, hydrochlorocarbons, fluorocarbons, deuterated hydrocarbons, deuterated hydrofluorocarbons, perfluorocarbons, fluoroethers, brominated compounds, iodinated compounds, alcohols, aldehydes, ketones, and nitrous oxide (N₂O). The tracer is particularly preferably a hydrofluorocarbon, a hydrochlorofluorocarbon, a chlorofluorocarbon, a fluorocarbon, a hydrochlorocarbon, a fluorocarbon, or a fluoroether.

The following compounds are preferable as the tracer.

FC-14 (tetrafluoromethane, CF₄) HCC-40 (chloromethane, CH₃Cl) HFC-23 (trifluoromethane, CHF₃) HFC-41 (fluoromethane, CH₃Cl) HFC-125 (pentafluoroethane, CF₃CHF₂) HFC-134a (1,1,1,2-tetrafluoroethane, CF₃CH₂F) HFC-134 (1,1,2,2-tetrafluoroethane, CHF₂CHF₂) HFC-143a (1,1,1-trifluoroethane, CF₃CH₃) HFC-143 (1,1,2-trifluoroethane, CHF₂CH₂F) HFC-152a (1,1-difluoroethane, CHF₂CH₃) HFC-152 (1,2-difluoroethane, CH₂FCH₂F) HFC-161 (fluoroethane, CH₃CH₂F) HFC-245fa (1,1,1,3,3-pentafluoropropane, CF₃CH₂CHF₂) HFC-236fa (1,1,1,3,3,3-hexafluoropropane, CF₃CH₂CF₃) HFC-236ea (1,1,1,2,3,3-hexafluoropropane, CF₃CHFCHF₂) HFC-227ea (1,1,1,2,3,3,3-heptafluoropropane, CF₃CHFCF₃) HCFC-22 (chlorodifluoromethane, CHClF₂) HCFC-31 (chlorofluoromethane, CH₂ClF) CFC-1113 (chlorotrifluoroethylene, CF₂═CClF) HFE-125 (trifluoromethyl-difluoromethyl ether, CF₃OCHF₂) HFE-134a (trifluoromethyl-fluoromethyl ether, CF₃OCH₂F) HFE-143a (trifluoromethyl-methyl ether, CF₃OCH₃) HFE-227ea (trifluoromethyl-tetrafluoroethyl ether, CF₃OCHFCF₃) HFE-236fa (trifluoromethyl-trifluoroethyl ether, CF₃OCH₂CF₃)

The tracer compound may be present in the refrigerant composition at a total concentration of about 10 parts per million (ppm) to about 1000 ppm. Preferably, the tracer compound is present in the refrigerant composition at a total concentration of about 30 ppm to about 500 ppm, and most preferably, the tracer compound is present at a total concentration of about 50 ppm to about 300 ppm.

(3-3) Ultraviolet Fluorescent Dye

The refrigerant composition according to the present disclosure may comprise a single ultraviolet fluorescent dye, or two or more ultraviolet fluorescent dyes.

The ultraviolet fluorescent dye is not limited, and can be suitably selected from commonly used ultraviolet fluorescent dyes.

Examples of ultraviolet fluorescent dyes include naphthalimide, coumarin, anthracene, phenanthrene, xanthene, thioxanthene, naphthoxanthene, fluorescein, and derivatives thereof. The ultraviolet fluorescent dye is particularly preferably either naphthalimide or coumarin, or both.

(3-4) Stabilizer

The refrigerant composition according to the present disclosure may comprise a single stabilizer, or two or more stabilizers.

The stabilizer is not limited, and can be suitably selected from commonly used stabilizers.

Examples of stabilizers include nitro compounds, ethers, and amines.

Examples of nitro compounds include aliphatic nitro compounds, such as nitromethane and nitroethane; and aromatic nitro compounds, such as nitro benzene and nitro styrene.

Examples of ethers include 1,4-dioxane.

Examples of amines include 2,2,3,3,3-pentafluoropropylamine and diphenylamine.

Examples of stabilizers also include butylhydroxyxylene and benzotriazole.

The content of the stabilizer is not limited. Generally, the content of the stabilizer is preferably 0.01 to 5 mass %, and more preferably 0.05 to 2 mass %, based on the entire refrigerant.

(3-5) Polymerization Inhibitor

The refrigerant composition according to the present disclosure may comprise a single polymerization inhibitor, or two or more polymerization inhibitors.

The polymerization inhibitor is not limited, and can be suitably selected from commonly used polymerization inhibitors.

Examples of polymerization inhibitors include 4-methoxy-1-naphthol, hydroquinone, hydroquinone methyl ether, dimethyl-t-butylphenol, 2,6-di-tert-butyl-p-cresol, and benzotriazole.

The content of the polymerization inhibitor is not limited. Generally, the content of the polymerization inhibitor is preferably 0.01 to 5 mass %, and more preferably 0.05 to 2 mass %, based on the entire refrigerant.

(4) Refrigeration Oil-Containing Working Fluid

The refrigeration oil-containing working fluid according to the present disclosure comprises at least the refrigerant or refrigerant composition according to the present disclosure and a refrigeration oil, for use as a working fluid in a refrigerating machine. Specifically, the refrigeration oil-containing working fluid according to the present disclosure is obtained by mixing a refrigeration oil used in a compressor of a refrigerating machine with the refrigerant or the refrigerant composition. The refrigeration oil-containing working fluid generally comprises 10 to 50 mass % of refrigeration oil.

(4-1) Refrigeration Oil

The refrigeration oil is not limited, and can be suitably selected from commonly used refrigeration oils. In this case, refrigeration oils that are superior in the action of increasing the miscibility with the mixture and the stability of the mixture, for example, are suitably selected as necessary.

The base oil of the refrigeration oil is preferably, for example, at least one member selected from the group consisting of polyalkylene glycols (PAG), polyol esters (POE), and polyvinyl ethers (PVE).

The refrigeration oil may further contain additives in addition to the base oil. The additive may be at least one member selected from the group consisting of antioxidants, extreme-pressure agents, acid scavengers, oxygen scavengers, copper deactivators, rust inhibitors, oil agents, and antifoaming agents.

A refrigeration oil with a kinematic viscosity of 5 to 400 cSt at 40° C. is preferable from the standpoint of lubrication.

The refrigeration oil-containing working fluid according to the present disclosure may further optionally contain at least one additive. Examples of additives include compatibilizing agents described below.

(4-2) Compatibilizing Agent

The refrigeration oil-containing working fluid according to the present disclosure may comprise a single compatibilizing agent, or two or more compatibilizing agents.

The compatibilizing agent is not limited, and can be suitably selected from commonly used compatibilizing agents.

Examples of compatibilizing agents include polyoxyalkylene glycol ethers, amides, nitriles, ketones, chlorocarbons, esters, lactones, aryl ethers, fluoroethers, and 1,1,1-trifluoroalkanes. The compatibilizing agent is particularly preferably a polyoxyalkylene glycol ether.

(5) Various Refrigerants

Hereinafter, the refrigerants which are the refrigerants used in the present embodiment, will be described in detail.

(5-4) Refrigerant D

The refrigerant D according to the present disclosure is a mixed refrigerant comprising trans-1,2-difluoroethylene (HFO-1132(E)), difluoromethane (R32), and 2,3,3,3-tetrafluoro-1-propene (R1234yf).

The refrigerant D according to the present disclosure has various properties that are desirable as an R410A-alternative refrigerant; i.e., a refrigerating capacity equivalent to that of R410A, a sufficiently low GWP, and a lower flammability (Class 2L) according to the ASHRAE standard.

The refrigerant D according to the present disclosure is preferably a refrigerant wherein

when the mass % of HFO-1132(E), R32, and R1234yf based on their sum is respectively represented by x, y, and z, coordinates (x,y,z) in a ternary composition diagram in which the sum of HFO-1132(E), R32, and R1234yf is 100 mass % are within the range of a figure surrounded by line segments IJ, JN, NE, and EI that connect the following 4 points:

point I (72.0, 0.0, 28.0), point J (48.5, 18.3, 33.2), point N (27.7, 18.2, 54.1), and point E (58.3, 0.0, 41.7), or on these line segments (excluding the points on the line segment EI);

the line segment IJ is represented by coordinates (0.0236y²−1.7616y+72.0, y, −0.0236y²+0.7616y+28.0);

the line segment NE is represented by coordinates (0.012y²−1.9003y+58.3, y, −0.012y²+0.9003y+41.7); and

the line segments JN and EI are straight lines. When the requirements above are satisfied, the refrigerant according to the present disclosure has a refrigerating capacity ratio of 80% or more relative to R410A, a GWP of 125 or less, and a WCF lower flammability.

The refrigerant D according to the present disclosure is preferably a refrigerant wherein

when the mass % of HFO-1132(E), R32, and R1234yf based on their sum is respectively represented by x, y, and z, coordinates (x,y,z) in a ternary composition diagram in which the sum of HFO-1132(E), R32, and R1234yf is 100 mass % are within the range of a figure surrounded by line segments MM′, M′N, NV, VG, and GM that connect the following 5 points:

point M (52.6, 0.0, 47.4), point M′ (39.2, 5.0, 55.8), point N (27.7, 18.2, 54.1), point V (11.0, 18.1, 70.9), and point G (39.6, 0.0, 60.4), or on these line segments (excluding the points on the line segment GM);

the line segment MM′ is represented by coordinates (0.132y²−3.34y+52.6, y, −0.132y²+2.34y+47.4);

the line segment M′N is represented by coordinates (0.0596y²−2.2541y+48.98, y, −0.0596y²+1.2541y+51.02);

the line segment VG is represented by coordinates (0.0123y²−1.8033y+39.6, y, −0.0123y²+0.8033y+60.4); and

the line segments NV and GM are straight lines. When the requirements above are satisfied, the refrigerant according to the present disclosure has a refrigerating capacity ratio of 70% or more relative to R410A, a GWP of 125 or less, and an ASHRAE lower flammability.

The refrigerant D according to the present disclosure is preferably a refrigerant wherein

when the mass % of HFO-1132(E), R32, and R1234yf based on their sum is respectively represented by x, y, and z, coordinates (x,y,z) in a ternary composition diagram in which the sum of HFO-1132(E), R32, and R1234yf is 100 mass % are within the range of a figure surrounded by line segments ON, NU, and UO that connect the following 3 points:

point O (22.6, 36.8, 40.6), point N (27.7, 18.2, 54.1), and point U (3.9, 36.7, 59.4), or on these line segments;

the line segment ON is represented by coordinates (0.0072y²−0.6701y+37.512, y, −0.0072y²−0.3299y+62.488);

the line segment NU is represented by coordinates (0.0083y²−1.7403y+56.635, y, −0.0083y²+0.7403y+43.365); and

the line segment UO is a straight line. When the requirements above are satisfied, the refrigerant according to the present disclosure has a refrigerating capacity ratio of 80% or more relative to R410A, a GWP of 250 or less, and an ASHRAE lower flammability.

The refrigerant D according to the present disclosure is preferably a refrigerant wherein

when the mass % of HFO-1132(E), R32, and R1234yf based on their sum is respectively represented by x, y, and z, coordinates (x,y,z) in a ternary composition diagram in which the sum of HFO-1132(E), R32, and R1234yf is 100 mass % are within the range of a figure surrounded by line segments QR, RT, TL, LK, and KQ that connect the following 5 points:

point Q (44.6, 23.0, 32.4), point R (25.5, 36.8, 37.7), point T (8.6, 51.6, 39.8), point L (28.9, 51.7, 19.4), and point K (35.6, 36.8, 27.6), or on these line segments;

the line segment QR is represented by coordinates (0.0099y²−1.975y+84.765, y, −0.0099y²+0.975y+15.235);

the line segment RT is represented by coordinates (0.0082y²−1.8683y+83.126, y, −0.0082y²+0.8683y+16.874);

the line segment LK is represented by coordinates (0.0049y²−0.8842y+61.488, y, −0.0049y²−0.1158y+38.512);

the line segment KQ is represented by coordinates (0.0095y²−1.2222y+67.676, y, −0.0095y²+0.2222y+32.324); and

the line segment TL is a straight line. When the requirements above are satisfied, the refrigerant according to the present disclosure has a refrigerating capacity ratio of 92.5% or more relative to R410A, a GWP of 350 or less, and a WCF lower flammability.

The refrigerant D according to the present disclosure is preferably a refrigerant wherein

when the mass % of HFO-1132(E), R32, and R1234yf based on their sum is respectively represented by x, y, and z, coordinates (x,y,z) in a ternary composition diagram in which the sum of HFO-1132(E), R32, and R1234yf is 100 mass % are within the range of a figure surrounded by line segments PS, ST, and TP that connect the following 3 points:

point P (20.5, 51.7, 27.8), point S (21.9, 39.7, 38.4), and point T (8.6, 51.6, 39.8), or on these line segments;

the line segment PS is represented by coordinates (0.0064y²−0.7103y+40.1, y, −0.0064y²−0.2897y+59.9);

the line segment ST is represented by coordinates (0.0082y²−1.8683y+83.126, y, −0.0082y²+0.8683y+16.874); and

the line segment TP is a straight line. When the requirements above are satisfied, the refrigerant according to the present disclosure has a refrigerating capacity ratio of 92.5% or more relative to R410A, a GWP of 350 or less, and an ASHRAE lower flammability.

The refrigerant D according to the present disclosure is preferably a refrigerant wherein

when the mass % of HFO-1132(E), R32, and R1234yf based on their sum is respectively represented by x, y, and z, coordinates (x,y,z) in a ternary composition diagram in which the sum of HFO-1132(E), R32, and R1234yf is 100 mass % are within the range of a figure surrounded by line segments ac, cf, fd, and da that connect the following 4 points:

point a (71.1, 0.0, 28.9), point c (36.5, 18.2, 45.3), point f (47.6, 18.3, 34.1), and point d (72.0, 0.0, 28.0), or on these line segments;

the line segment ac is represented by coordinates (0.0181y²−2.2288y+71.096, y, −0.0181y²+1.2288y+28.904);

the line segment fd is represented by coordinates (0.02y²−1.7y+72, y, −0.02y²+0.7y+28); and

the line segments cf and da are straight lines. When the requirements above are satisfied, the refrigerant according to the present disclosure has a refrigerating capacity ratio of 85% or more relative to R410A, a GWP of 125 or less, and a lower flammability (Class 2L) according to the ASHRAE standard.

The refrigerant D according to the present disclosure is preferably a refrigerant wherein

when the mass % of HFO-1132(E), R32, and R1234yf based on their sum is respectively represented by x, y, and z, coordinates (x,y,z) in a ternary composition diagram in which the sum of HFO-1132(E), R32, and R1234yf is 100 mass % are within the range of a figure surrounded by line segments ab, be, ed, and da that connect the following 4 points:

point a (71.1, 0.0, 28.9), point b (42.6, 14.5, 42.9), point e (51.4, 14.6, 34.0), and point d (72.0, 0.0, 28.0), or on these line segments;

the line segment ab is represented by coordinates (0.0181y²−2.2288y+71.096, y, −0.0181y²+1.2288y+28.904);

the line segment ed is represented by coordinates (0.02y²−1.7y+72, y, −0.02y²+0.7y+28); and

the line segments be and da are straight lines. When the requirements above are satisfied, the refrigerant according to the present disclosure has a refrigerating capacity ratio of 85% or more relative to R410A, a GWP of 100 or less, and a lower flammability (Class 2L) according to the ASHRAE standard.

The refrigerant D according to the present disclosure is preferably a refrigerant wherein

when the mass % of HFO-1132(E), R32, and R1234yf based on their sum is respectively represented by x, y, and z, coordinates (x,y,z) in a ternary composition diagram in which the sum of HFO-1132(E), R32, and R1234yf is 100 mass % are within the range of a figure surrounded by line segments gi, ij, and jg that connect the following 3 points:

point g (77.5, 6.9, 15.6), point i (55.1, 18.3, 26.6), and point j (77.5. 18.4, 4.1), or on these line segments;

the line segment gi is represented by coordinates (0.02y²−2.4583y+93.396, y, −0.02y²+1.4583y+6.604); and

the line segments ij and jg are straight lines. When the requirements above are satisfied, the refrigerant according to the present disclosure has a refrigerating capacity ratio of 95% or more relative to R410A and a GWP of 100 or less, undergoes fewer or no changes such as polymerization or decomposition, and also has excellent stability.

The refrigerant D according to the present disclosure is preferably a refrigerant wherein

when the mass % of HFO-1132(E), R32, and R1234yf based on their sum is respectively represented by x, y, and z, coordinates (x,y,z) in a ternary composition diagram in which the sum of HFO-1132(E), R32, and R1234yf is 100 mass % are within the range of a figure surrounded by line segments gh, hk, and kg that connect the following 3 points:

point g (77.5, 6.9, 15.6), point h (61.8, 14.6, 23.6), and point k (77.5, 14.6, 7.9), or on these line segments;

the line segment gh is represented by coordinates (0.02y²−2.4583y+93.396, y, −0.02y²+1.4583y+6.604); and

the line segments hk and kg are straight lines. When the requirements above are satisfied, the refrigerant according to the present disclosure has a refrigerating capacity ratio of 95% or more relative to R410A and a GWP of 100 or less, undergoes fewer or no changes such as polymerization or decomposition, and also has excellent stability.

The refrigerant D according to the present disclosure may further comprise other additional refrigerants in addition to HFO-1132(E), R32, and R1234yf, as long as the above properties and effects are not impaired. In this respect, the refrigerant according to the present disclosure preferably comprises HFO-1132(E), R32, and R1234yf in a total amount of 99.5 mass % or more, more preferably 99.75 mass % or more, and still more preferably 99.9 mass % or more based on the entire refrigerant.

Such additional refrigerants are not limited, and can be selected from a wide range of refrigerants. The mixed refrigerant may comprise a single additional refrigerant, or two or more additional refrigerants.

(Examples of Refrigerant D)

The present disclosure is described in more detail below with reference to Examples of refrigerant D. However, the refrigerant D is not limited to the Examples.

The composition of each mixed refrigerant of HFO-1132(E), R32, and R1234yf was defined as WCF. A leak simulation was performed using the NIST Standard Reference Database REFLEAK Version 4.0 under the conditions of Equipment, Storage, Shipping, Leak, and Recharge according to the ASHRAE Standard 34-2013. The most flammable fraction was defined as WCFF.

A burning velocity test was performed using the apparatus shown in FIG. 1 in the following manner. First, the mixed refrigerants used had a purity of 99.5% or more, and were degassed by repeating a cycle of freezing, pumping, and thawing until no traces of air were observed on the vacuum gauge. The burning velocity was measured by the closed method. The initial temperature was ambient temperature. Ignition was performed by generating an electric spark between the electrodes in the center of a sample cell. The duration of the discharge was 1.0 to 9.9 ms, and the ignition energy was typically about 0.1 to 1.0 J. The spread of the flame was visualized using schlieren photographs. A cylindrical container (inner diameter: 155 mm, length: 198 mm) equipped with two light transmission acrylic windows was used as the sample cell, and a xenon lamp was used as the light source. Schlieren images of the flame were recorded by a high-speed digital video camera at a frame rate of 600 fps and stored on a PC. Tables 1 to 3 show the results.

TABLE 1 Comparative Example Example Example Example 13 Example 12 Example 14 Example 16 Item Unit I 11 J 13 K 15 L WCF HFO- Mass % 72 57.2 48.5 41.2 35.6 32 28.9 1132 (E) R32 Mass % 0 10 18.3 27.6 36.8 44.2 51.7 R1234yf Mass % 28 32.8 33.2 31.2 27.6 23.8 19.4 Burning Velocity cm/s 10 10 10 10 10 10 10 (WCF)

TABLE 2 Comparative Example Example Example 14 Example 19 Example 21 Example Item Unit M 18 W 20 N 22 WCF HFO-1132 Mass % 52.6 39.2 32.4 29.3 27.7 24.6 (E) R32 Mass % 0.0 5.0 10.0 14.5 18.2 27.6 R1234yf Mass % 47.4 55.8 57.6 56.2 54.1 47.8 Leak condition that Storage, Storage, Storage, Storage, Storage, Storage, results in WCFF Shipping, Shipping, Shipping, Shipping, Shipping, Shipping, −40° C., −40° C., −40° C., −40° C., −40° C., −40° C., 0% 0% 0% 0% 0% 0% release, on release, on release, on release, on release, on release, on the gas the gas the gas the gas the gas the gas phase side phase side phase side phase side phase side phase side WCF HFO-1132 Mass % 72.0 57.8 48.7 43.6 40.6 34.9 (E) R32 Mass % 0.0 9.5 17.9 24.2 28.7 38.1 R1234yf Mass % 28.0 32.7 33.4 32.2 30.7 27.0 Burning Velocity cm/s 8 or less 8 or less 8 or less 8 or less 8 or less 8 or less (WCF) Burning Velocity cm/s 10 10 10 10 10 10 (WCFF)

TABLE 3 Example 23 Example 25 Item Unit O Example 24 P WCF HFO-1132 (E) Mass % 22.6 21.2 20.5 HFO-1123 Mass % 36.8 44.2 51.7 R1234yf Mass % 40.6 34.6 27.8 Leak condition that results in WCFF Storage, Storage, Shipping, Shipping, Shipping, −40° C., −40° C., −40° C., 0% release, on 0% release, on 0% release, on the gas phase the gas phase the gas phase side side side WCFF HFO-1132 (E) Mass % 31.4 29.2 27.1 HFO-1123 Mass % 45.7 51.1 56.4 R1234yf Mass % 23.0 19.7 16.5 Burning Velocity (WCF) cm/s 8 or less 8 or less Burning Velocity (WCFF) cm/s 10 10 10

The results indicate that under the condition that the mass % of HFO-1132(E), R32, and R1234yf based on their sum is respectively represented by x, y, and z, when coordinates (x,y,z) in the ternary composition diagram shown in FIG. 2 in which the sum of HFO-1132(E), R32, and R1234yf is 100 mass % are on the line segment that connects point I, point J, point K, and point L, or below these line segments, the refrigerant has a WCF lower flammability.

The results also indicate that when coordinates (x,y,z) in the ternary composition diagram shown in FIG. 2 are on the line segments that connect point M, point M′, point W, point J, point N, and point P, or below these line segments, the refrigerant has an ASHRAE lower flammability.

Mixed refrigerants were prepared by mixing HFO-1132(E), R32, and R1234yf in amounts (mass %) shown in Tables 4 to 32 based on the sum of HFO-1132(E), R32, and R1234yf. The coefficient of performance (COP) ratio and the refrigerating capacity ratio relative to R410 of the mixed refrigerants shown in Tables 116 to 144 were determined. The conditions for calculation were as described below.

Evaporating temperature: 5° C.

Condensation temperature: 45° C.

Degree of superheating: 5 K

Degree of subcooling: 5 K

Compressor efficiency: 70%

Tables 4 to 32 show these values together with the GWP of each mixed refrigerant.

TABLE 4 Comparative Comparative Comparative Comparative Comparative Comparative Comparative Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Item Unit Example 1 A B A′ B′ A″ B″ HFO-1132(E) Mass % R410A 81.6 0.0 63.1 0.0 48.2 0.0 R32 Mass % 18.4 18.1 36.9 36.7 51.8 51.5 R1234yf Mass % 0.0 81.9 0.0 63.3 0.0 48.5 GWP — 2088 125 125 250 250 350 350 COP Ratio % (relative to 100 98.7 103.6 98.7 102.3 99.2 102.2 R410A) Refrigerating % (relative to 100 105.3 62.5 109.9 77.5 112.1 87.3 Capacity R410A) Ratio

TABLE 5 Comparative Comparative Example Example Example 8 Comparative Example 10 Example 2 Example 4 Item Unit C Example 9 C′ 1 R 3 T HFO-1132(E) Mass % 85.5 66.1 52.1 37.8 25.5 16.6 8.6 R32 Mass % 0.0 10.0 18.2 27.6 36.8 44.2 51.6 R1234yf Mass % 14.5 23.9 29.7 34.6 37.7 39.2 39.8 GWP — 1 69 125 188 250 300 350 COP Ratio % (relative to 99.8 99.3 99.3 99.6 100.2 100.8 101.4 R410A) Refrigerating % (relative to 92.5 92.5 92.5 92.5 92.5 92.5 92.5 Capacity R410A) Ratio

TABLE 6 Comparative Example Example Comparative Example Example 11 Example 6 Example 8 Example 12 Example 10 Item Unit E 5 N 7 U G 9 V HFO-1132(E) Mass % 58.3 40.5 27.7 14.9 3.9 39.6 22.8 11.0 R32 Mass % 0.0 10.0 18.2 27.6 36.7 0.0 10.0 18.1 R1234yf Mass % 41.7 49.5 54.1 57.5 59.4 60.4 67.2 70.9 GWP — 2 70 125 189 250 3 70 125 COP Ratio % (relative to 100.3 100.3 100.7 101.2 101.9 101.4 101.8 102.3 R410A) Refrigerating % (relative to 80.0 80.0 80.0 80.0 80.0 70.0 70.0 70.0 Capacity R410A) Ratio

TABLE 7 Comparative Example Example Example Example Example 13 Example 12 Example 14 Example 16 17 Item Unit I 11 J 13 K 15 L Q HFO-1132(E) Mass % 72.0 57.2 48.5 41.2 35.6 32.0 28.9 44.6 R32 Mass % 0.0 10.0 18.3 27.6 36.8 44.2 51.7 23.0 R1234yf Mass % 28.0 32.8 33.2 31.2 27.6 23.8 19.4 32.4 GWP — 2 69 125 188 250 300 350 157 COP Ratio % (relative to 99.9 99.5 99.4 99.5 99.6 99.8 100.1 99.4 R410A) Refrigerating % (relative to 86.6 88.4 90.9 94.2 97.7 100.5 103.3 92.5 Capacity R410A) Ratio

TABLE 8 Comparative Example Example Example 14 Example 19 Example 21 Example Item Unit M 18 W 20 N 22 HFO-1132(E) Mass % 52.6 39.2 32.4 29.3 27.7 24.5 R32 Mass % 0.0 5.0 10.0 14.5 18.2 27.6 R1234yf Mass % 47.4 55.8 57.6 56.2 54.1 47.9 GWP — 2 36 70 100 125 188 COP Ratio % (relative to 100.5 100.9 100.9 100.8 100.7 100.4 R410A) Refrigerating % (relative to 77.1 74.8 75.6 77.8 80.0 85.5 Capacity R410A) Ratio

TABLE 9 Example 23 Example 25 Example 26 Item Unit O Example 24 P S HFO-1132(E) Mass % 22.6 21.2 20.5 21.9 R32 Mass % 36.8 44.2 51.7 39.7 R1234yf Mass % 40.6 34.6 27.8 38.4 GWP — 250 300 350 270 COP Ratio % (relative to 100.4 100.5 100.6 100.4 R410A) Refrigerating Capacity % (relative to 91.0 95.0 99.1 92.5 Ratio R410A)

TABLE 10 Comparative Comparative Comparative Comparative Example Example Comparative Comparative Item Unit Example 15 Example 16 Example 17 Example 18 27 28 Example 19 Example 20 HFO-1132(E) Mass % 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 R32 Mass % 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0 R1234yf Mass % 85.0 75.0 65.0 55.0 45.0 35.0 25.0 15.0 GWP — 37 37 37 36 36 36 35 35 COP Ratio % (relative to 103.4 102.6 101.6 100.8 100.2 99.8 99.6 99.4 R410A) Refrigerating % (relative to 56.4 63.3 69.5 75.2 80.5 85.4 90.1 94.4 Capacity R410A) Ratio

TABLE 11 Comparative Comparative Example Comparative Example Comparative Comparative Comparative Item Unit Example 21 Example 22 29 Example 23 30 Example 24 Example 25 Example 26 HFO-1132(E) Mass % 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 R32 Mass % 10.0 10.0 10.0 10.0 10.0 10.0 10.0 10.0 R1234yf Mass % 80.0 70.0 60.0 50.0 40.0 30.0 20.0 10.0 GWP — 71 71 70 70 70 69 69 69 COP Ratio % (relative to 103.1 102.1 101.1 100.4 99.8 99.5 99.2 99.1 R410A) Refrigerating % (relative to 61.8 68.3 74.3 79.7 84.9 89.7 94.2 98.4 Capacity R410A) Ratio

TABLE 12 Comparative Example Comparative Example Example Comparative Comparative Comparative Item Unit Example 27 31 Example 28 32 33 Example 29 Example 30 Example 31 HFO-1132(E) Mass % 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 R32 Mass % 15.0 15.0 15.0 15.0 15.0 15.0 15.0 15.0 R1234yf Mass % 75.0 65.0 55.0 45.0 35.0 25.0 15.0 5.0 GWP — 104 104 104 103 103 103 103 102 COP Ratio % (relative to 102.7 101.6 100.7 100.0 99.5 99.2 99.0 98.9 R410A) Refrigerating % (relative to 66.6 72.9 78.6 84.0 89.0 93.7 98.1 102.2 Capacity R410A) Ratio

TABLE 13 Comparative Comparative Comparative Comparative Comparative Comparative Comparative Comparative Item Unit Example 32 Example 33 Example 34 Example 35 Example 36 Example 37 Example 38 Example 39 HFO-1132(E) Mass % 10.0 20.0 30.0 40.0 50.0 60.0 70.0 10.0 R32 Mass % 20.0 20.0 20.0 20.0 20.0 20.0 20.0 25.0 R1234yf Mass % 70.0 60.0 50.0 40.0 30.0 20.0 10.0 65.0 GWP — 138 138 137 137 137 136 136 171 COP Ratio % (relative to 102.3 101.2 100.4 99.7 99.3 99.0 98.8 101.9 R410A) Refrigerating % (relative to 71.0 77.1 82.7 88.0 92.9 97.5 101.7 75.0 Capacity R410A) Ratio

TABLE 14 Example Comparative Comparative Comparative Comparative Comparative Comparative Example Item Unit 34 Example 40 Example 41 Example 42 Example 43 Example 44 Example 45 35 HFO-1132(E) Mass % 20.0 30.0 40.0 50.0 60.0 70.0 10.0 20.0 R32 Mass % 25.0 25.0 25.0 25.0 25.0 25.0 30.0 30.0 R1234yf Mass % 55.0 45.0 35.0 25.0 15.0 5.0 60.0 50.0 GWP — 171 171 171 170 170 170 205 205 COP Ratio % (relative to 100.9 100.1 99.6 99.2 98.9 98.7 101.6 100.7 R410A) Refrigerating % (relative to 81.0 86.6 91.7 96.5 101.0 105.2 78.9 84.8 Capacity R410A) Ratio

TABLE 15 Comparative Comparative Comparative Comparative Example Example Example Comparative Item Unit Example 46 Example 47 Example 48 Example 49 36 37 38 Example 50 HFO-1132(E) Mass % 30.0 40.0 50.0 60.0 10.0 20.0 30.0 40.0 R32 Mass % 30.0 30.0 30.0 30.0 35.0 35.0 35.0 35.0 R1234yf Mass % 40.0 30.0 20.0 10.0 55.0 45.0 35.0 25.0 GWP — 204 204 204 204 239 238 238 238 COP Ratio % (relative to 100.0 99.5 99.1 98.8 101.4 100.6 99.9 99.4 R410A) Refrigerating % (relative to 90.2 95.3 100.0 104.4 82.5 88.3 93.7 98.6 Capacity R410A) Ratio

TABLE 16 Comparative Comparative Comparative Comparative Example Comparative Comparative Comparative Item Unit Example 51 Example 52 Example 53 Example 54 39 Example 55 Example 56 Example 57 HFO-1132(E) Mass % 50.0 60.0 10.0 20.0 30.0 40.0 50.0 10.0 R32 Mass % 35.0 35.0 40.0 40.0 40.0 40.0 40.0 45.0 R1234yf Mass % 15.0 5.0 50.0 40.0 30.0 20.0 10.0 45.0 GWP — 237 237 272 272 272 271 271 306 COP Ratio % (relative to 99.0 98.8 101.3 100.6 99.9 99.4 99.0 101.3 R410A) Refrigerating % (relative to 103.2 107.5 86.0 91.7 96.9 101.8 106.3 89.3 Capacity R410A) Ratio

TABLE 17 Comparative Comparative Comparative Comparative Comparative Item Unit Example 40 Example 41 Example 58 Example 59 Example 60 Example 42 Example 61 Example 62 HFO-1132(E) Mass % 20.0 30.0 40.0 50.0 10.0 20.0 30.0 40.0 R32 Mass % 45.0 45.0 45.0 45.0 50.0 50.0 50.0 50.0 R1234yf Mass % 35.0 25.0 15.0 5.0 40.0 30.0 20.0 10.0 GWP — 305 305 305 304 339 339 339 338 COP Ratio %(relative 100.6 100.0 99.5 99.1 101.3 100.6 100.0 99.5 to R410A) Refrigerating %(relative 94.9 100.0 104.7 109.2 92.4 97.8 102.9 107.5 Capacity Ratio to R410A)

TABLE 18 Comparative Comparative Comparative Comparative Item Unit Example 63 Example 64 Example 65 Example 66 Example 43 Example 44 Example 45 Example 46 HFO-1132(E) Mass % 10.0 20.0 30.0 40.0 56.0 59.0 62.0 65.0 R32 Mass % 55.0 55.0 55.0 55.0 3.0 3.0 3.0 3.0 R1234yf Mass % 35.0 25.0 15.0 5.0 41.0 38.0 35.0 32.0 GWP — 373 372 372 372 22 22 22 22 COP Ratio %(relative 101.4 100.7 100.1 99.6 100.1 100.0 99.9 99.8 to R410A) Refrigerating %(relative 95.3 100.6 105.6 110.2 81.7 83.2 84.6 86.0 Capacity Ratio to R410A)

TABLE 19 Item Unit Example 47 Example 48 Example 49 Example 50 Example 51 Example 52 Example 53 Example 54 HFO-1132(E) Mass % 49.0 52.0 55.0 58.0 61.0 43.0 46.0 49.0 R32 Mass % 6.0 6.0 6.0 6.0 6.0 9.0 9.0 9.0 R1234yf Mass % 45.0 42.0 39.0 36.0 33.0 48.0 45.0 42.0 GWP — 43 43 43 43 42 63 63 63 COP Ratio %(relative 100.2 100.0 99.9 99.8 99.7 100.3 100.1 99.9 to R410A) Refrigerating %(relative 80.9 82.4 83.9 85.4 86.8 80.4 82.0 83.5 Capacity Ratio to R410A)

TABLE 20 Item Unit Example 55 Example 56 Example 57 Example 58 Example 59 Example 60 Example 61 Example 62 HFO-1132(E) Mass % 52.0 55.0 58.0 38.0 41.0 44.0 47.0 50.0 R32 Mass % 9.0 9.0 9.0 12.0 12.0 12.0 12.0 12.0 R1234yf Mass % 39.0 36.0 33.0 50.0 47.0 44.0 41.0 38.0 GWP — 63 63 63 83 83 83 83 83 COP Ratio %(relative 99.8 99.7 99.6 100.3 100.1 100.0 99.8 99.7 to R410A) Refrigerating %(relative 85.0 86.5 87.9 80.4 82.0 83.5 85.1 86.6 Capacity Ratio to R410A)

TABLE 21 Item Unit Example 63 Example 64 Example 65 Example 66 Example 67 Example 68 Example 69 Example 70 HFO-1132(E) Mass % 53.0 33.0 36.0 39.0 42.0 45.0 48.0 51.0 R32 Mass % 12.0 15.0 15.0 15.0 15.0 15.0 15.0 15.0 R1234yf Mass % 35.0 52.0 49.0 46.0 43.0 40.0 37.0 34.0 GWP — 83 104 104 103 103 103 103 103 COP Ratio %(relative 99.6 100.5 100.3 100.1 99.9 99.7 99.6 99.5 to R410A) Refrigerating %(relative 88.0 80.3 81.9 83.5 85.0 86.5 88.0 89.5 Capacity Ratio to R410A)

TABLE 22 Item Unit Example 71 Example 72 Example 73 Example 74 Example 75 Example 76 Example 77 Example 78 HFO-1132(E) Mass % 29.0 32.0 35.0 38.0 41.0 44.0 47.0 36.0 R32 Mass % 18.0 18.0 18.0 18.0 18.0 18.0 18.0 3.0 R1234yf Mass % 53.0 50.0 47.0 44.0 41.0 38.0 35.0 61.0 GWP — 124 124 124 124 124 123 123 23 COP Ratio %(relative 100.6 100.3 100.1 99.9 99.8 99.6 99.5 101.3 to R410A) Refrigerating %(relative 80.6 82.2 83.8 85.4 86.9 88.4 89.9 71.0 Capacity Ratio to R410A)

TABLE 23 Item Unit Example 79 Example 80 Example 81 Example 82 Example 83 Example 84 Example 85 Example 86 HFO-1132(E) Mass % 39.0 42.0 30.0 33.0 36.0 26.0 29.0 32.0 R32 Mass % 3.0 3.0 6.0 6.0 6.0 9.0 9.0 9.0 R1234yf Mass % 58.0 55.0 64.0 61.0 58.0 65.0 62.0 59.0 GWP — 23 23 43 43 43 64 64 63 COP Ratio %(relative 101.1 100.9 101.5 101.3 101.0 101.6 101.3 101.1 to R410A) Refrigerating %(relative 72.7 74.4 70.5 72.2 73.9 71.0 72.8 74.5 Capacity Ratio to R410A)

TABLE 24 Item Unit Example 87 Example 88 Example 89 Example 90 Example 91 Example 92 Example 93 Example 94 HFO-1132(E) Mass % 21.0 24.0 27.0 30.0 16.0 19.0 22.0 25.0 R32 Mass % 12.0 12.0 12.0 12.0 15.0 15.0 15.0 15.0 R1234yf Mass % 67.0 64.0 61.0 58.0 69.0 66.0 63.0 60.0 GWP — 84 84 84 84 104 104 104 104 COP Ratio %(relative 101.8 101.5 101.2 101.0 102.1 101.8 101.4 101.2 to R410A) Refrigerating %(relative 70.8 72.6 74.3 76.0 70.4 72.3 74.0 75.8 Capacity Ratio to R410A)

TABLE 25 Item Unit Example 95 Example 96 Example 97 Example 98 Example 99 Example 100 Example 101 Example 102 HFO-1132(E) Mass % 28.0 12.0 15.0 18.0 21.0 24.0 27.0 25.0 R32 Mass % 15.0 18.0 18.0 18.0 18.0 18.0 18.0 21.0 R1234yf Mass % 57.0 70.0 67.0 64.0 61.0 58.0 55.0 54.0 GWP — 104 124 124 124 124 124 124 144 COP Ratio %(relative 100.9 102.2 101.9 101.6 101.3 101.0 100.7 100.7 to R410A) Refrigerating %(relative 77.5 70.5 72.4 74.2 76.0 77.7 79.4 80.7 Capacity Ratio to R410A)

TABLE 26 Item Unit Example 103 Example 104 Example 105 Example 106 Example 107 Example 108 Example 109 Example 110 HFO-1132(E) Mass % 21.0 24.0 17.0 20.0 23.0 13.0 16.0 19.0 R32 Mass % 24.0 24.0 27.0 27.0 27.0 30.0 30.0 30.0 R1234yf Mass % 55.0 52.0 56.0 53.0 50.0 57.0 54.0 51.0 GWP — 164 164 185 185 184 205 205 205 COP Ratio %(relative 100.9 100.6 101.1 100.8 100.6 101.3 101.0 100.8 to R410A) Refrigerating %(relative 80.8 82.5 80.8 82.5 84.2 80.7 82.5 84.2 Capacity Ratio to R410A)

TABLE 27 Item Unit Example 111 Example 112 Example 113 Example 114 Example 115 Example 116 Example 117 Example 118 HFO-1132(E) Mass % 22.0 9.0 12.0 15.0 18.0 21.0 8.0 12.0 R32 Mass % 30.0 33.0 33.0 33.0 33.0 33.0 36.0 36.0 R1234yf Mass % 48.0 58.0 55.0 52.0 49.0 46.0 56.0 52.0 GWP — 205 225 225 225 225 225 245 245 COP Ratio %(relative 100.5 101.6 101.3 101.0 100.8 100.5 101.6 101.2 to R410A) Refrigerating %(relative 85.9 80.5 82.3 84.1 85.8 87.5 82.0 84.4 Capacity Ratio to R410A)

TABLE 28 Item Unit Example 119 Example 120 Example 121 Example 122 Example 123 Example 124 Example 125 Example 126 HFO-1132(E) Mass % 15.0 18.0 21.0 42.0 39.0 34.0 37.0 30.0 R32 Mass % 36.0 36.0 36.0 25.0 28.0 31.0 31.0 34.0 R1234yf Mass % 49.0 46.0 43.0 33.0 33.0 35.0 32.0 36.0 GWP — 245 245 245 170 191 211 211 231 COP Ratio %(relative 101.0 100.7 100.5 99.5 99.5 99.8 99.6 99.9 to R410A) Refrigerating %(relative 86.2 87.9 89.6 92.7 93.4 93.0 94.5 93.0 Capacity Ratio to R410A)

TABLE 29 Item Unit Example 127 Example 128 Example 129 Example 130 Example 131 Example 132 Example 133 Example 134 HFO-1132(E) Mass % 33.0 36.0 24.0 27.0 30.0 33.0 23.0 26.0 R32 Mass % 34.0 34.0 37.0 37.0 37.0 37.0 40.0 40.0 R1234yf Mass % 33.0 30.0 39.0 36.0 33.0 30.0 37.0 34.0 GWP — 231 231 252 251 251 251 272 272 COP Ratio %(relative 99.8 99.6 100.3 100.1 99.9 99.8 100.4 100.2 to R410A) Refrigerating %(relative 94.5 96.0 91.9 93.4 95.0 96.5 93.3 94.9 Capacity Ratio to R410A)

TABLE 30 Item Unit Example 135 Example 136 Example 137 Example 138 Example 139 Example 140 Example 141 Example 142 HFO-1132(E) Mass % 29.0 32.0 19.0 22.0 25.0 28.0 31.0 18.0 R32 Mass % 40.0 40.0 43.0 43.0 43.0 43.0 43.0 46.0 R1234yf Mass % 31.0 28.0 38.0 35.0 32.0 29.0 26.0 36.0 GWP — 272 271 292 292 292 292 292 312 COP Ratio %(relative 100.0 99.8 100.6 100.4 100.2 100.1 99.9 100.7 to R410A) Refrigerating %(relative 96.4 97.9 93.1 94.7 96.2 97.8 99.3 94.4 Capacity Ratio to R410A)

TABLE 31 Item Unit Example 143 Example 144 Example 145 Example 146 Example 147 Example 148 Example 149 Example 150 HFO-1132(E) Mass % 21.0 23.0 26.0 29.0 13.0 16.0 19.0 22.0 R32 Mass % 46.0 46.0 46.0 46.0 49.0 49.0 49.0 49.0 R1234yf Mass % 33.0 31.0 28.0 25.0 38.0 35.0 32.0 29.0 GWP — 312 312 312 312 332 332 332 332 COP Ratio %(relative 100.5 100.4 100.2 100.0 101.1 100.9 100.7 100.5 to R410A) Refrigerating %(relative 96.0 97.0 98.6 100.1 93.5 95.1 96.7 98.3 Capacity Ratio to R410A)

TABLE 32 Item Unit Example 151 Example 152 HFO-1132(E) Mass % 25.0 28.0 R32 Mass % 49.0 49.0 R1234yf Mass % 26.0 23.0 GWP — 332 332 COP Ratio % (relative to 100.3 100.1 R410A) Refrigerating Capacity % (relative to 99.8 101.3 Ratio R410A)

The results also indicate that under the condition that the mass % of HFO-1132(E), R32, and R1234yf based on their sum is respectively represented by x, y, and z, when coordinates (x,y,z) in a ternary composition diagram in which the sum of HFO-1132(E), R32, and R1234yf is 100 mass % are within the range of a figure surrounded by line segments IJ, JN, NE, and EI that connect the following 4 points:

point I (72.0, 0.0, 28.0), point J (48.5, 18.3, 33.2), point N (27.7, 18.2, 54.1), and point E (58.3, 0.0, 41.7), or on these line segments (excluding the points on the line segment EI),

the line segment IJ is represented by coordinates (0.0236y²−1.7616y+72.0, y, −0.0236y²+0.7616y+28.0),

the line segment NE is represented by coordinates (0.012y²−1.9003y+58.3, y, −0.012y²+0.9003y+41.7), and

the line segments JN and EI are straight lines, the refrigerant D has a refrigerating capacity ratio of 80% or more relative to R410A, a GWP of 125 or less, and a WCF lower flammability.

The results also indicate that under the condition that the mass % of HFO-1132(E), R32, and R1234yf based on their sum is respectively represented by x, y, and z, when coordinates (x,y,z) in a ternary composition diagram in which the sum of HFO-1132(E), R32, and R1234yf is 100 mass % are within the range of a figure surrounded by line segments MM′, M′N, NV, VG, and GM that connect the following 5 points:

point M (52.6, 0.0, 47.4), point M′ (39.2, 5.0, 55.8), point N (27.7, 18.2, 54.1), point V (11.0, 18.1, 70.9), and point G (39.6, 0.0, 60.4), or on these line segments (excluding the points on the line segment GM),

the line segment MM′ is represented by coordinates (0.132y²−3.34y+52.6, y, −0.132y²+2.34y+47.4),

the line segment M′N is represented by coordinates (0.0596y²−2.2541y+48.98, y, −0.0596y²+1.2541y+51.02),

the line segment VG is represented by coordinates (0.0596y²−2.2541y+48.98, y, −0.0596y²+1.2541y+51.02), and

the line segments NV and GM are straight lines, the refrigerant D according to the present disclosure has a refrigerating capacity ratio of 70% or more relative to R410A, a GWP of 125 or less, and an ASHRAE lower flammability.

The results also indicate that under the condition that the mass % of HFO-1132(E), R32, and R1234yf based on their sum is respectively represented by x, y, and z, when coordinates (x,y,z) in a ternary composition diagram in which the sum of HFO-1132(E), R32, and R1234yf is 100 mass % are within the range of a figure surrounded by line segments ON, NU, and UO that connect the following 3 points:

point O (22.6, 36.8, 40.6), point N (27.7, 18.2, 54.1), and point U (3.9, 36.7, 59.4), or on these line segments,

the line segment ON is represented by coordinates (0.0072y²−0.6701y+37.512, y, −0.0072y²−0.3299y+62.488),

the line segment NU is represented by coordinates (0.0083y²−1.7403y+56.635, y, −0.0083y²+0.7403y+43.365), and

the line segment UO is a straight line, the refrigerant D according to the present disclosure has a refrigerating capacity ratio of 80% or more relative to R410A, a GWP of 250 or less, and an ASHRAE lower flammability.

The results also indicate that under the condition that the mass % of HFO-1132(E), R32, and R1234yf based on their sum is respectively represented by x, y, and z, when coordinates (x,y,z) in a ternary composition diagram in which the sum of HFO-1132(E), R32, and R1234yf is 100 mass % are within the range of a figure surrounded by line segments QR, RT, TL, LK, and KQ that connect the following 5 points:

point Q (44.6, 23.0, 32.4), point R (25.5, 36.8, 37.7), point T (8.6, 51.6, 39.8), point L (28.9, 51.7, 19.4), and point K (35.6, 36.8, 27.6), or on these line segments,

the line segment QR is represented by coordinates (0.0099y²−1.975y+84.765, y, −0.0099y²+0.975y+15.235),

the line segment RT is represented by coordinates (0.0082y²−1.8683y+83.126, y, −0.0082y²+0.8683y+16.874),

the line segment LK is represented by coordinates (0.0049y²−0.8842y+61.488, y, −0.0049y²−0.1158y+38.512),

the line segment KQ is represented by coordinates (0.0095y²−1.2222y+67.676, y, −0.0095y²+0.2222y+32.324), and

the line segment TL is a straight line, the refrigerant D according to the present disclosure has a refrigerating capacity ratio of 92.5% or more relative to R410A, a GWP of 350 or less, and a WCF lower flammability.

The results further indicate that under the condition that the mass % of HFO-1132(E), R32, and R1234yf based on their sum is respectively represented by x, y, and z, when coordinates (x,y,z) in a ternary composition diagram in which the sum of HFO-1132(E), R32, and R1234yf is 100 mass % are within the range of a figure surrounded by line segments PS, ST, and TP that connect the following 3 points:

point P (20.5, 51.7, 27.8), point S (21.9, 39.7, 38.4), and point T (8.6, 51.6, 39.8), or on these line segments,

the line segment PS is represented by coordinates (0.0064y²−0.7103y+40.1, y, −0.0064y²−0.2897y+59.9),

the line segment ST is represented by coordinates (0.0082y²−1.8683y+83.126, y, −0.0082y²+0.8683y+16.874), and

the line segment TP is a straight line, the refrigerant D according to the present disclosure has a refrigerating capacity ratio of 92.5% or more relative to R410A, a GWP of 350 or less, and an ASHRAE lower flammability.

(6) First Embodiment

FIG. 3 is a configuration diagram of an air conditioner 1 according to a first embodiment of the present disclosure. In FIG. 3 , the air conditioner 1 is constituted by a utilization unit 2 and a heat source unit 3.

(6-1) Configuration of Air Conditioner 1

The air conditioner 1 has a refrigerant circuit 11 in which a compressor 100, a four-way switching valve 16, a heat-source-side heat exchanger 17, an expansion valve 18 serving as a decompression mechanism, and a utilization-side heat exchanger 13 are connected in a loop shape by refrigerant pipes.

In this embodiment, the refrigerant circuit 11 is filled with refrigerant for performing a vapor compression refrigeration cycle. The refrigerant is a refrigerant mixture containing 1,2-difluoroethylene, and any one of the above-described refrigerant A to refrigerant E can be used. The refrigerant circuit 11 is filled with refrigerating machine oil together with the refrigerant mixture.

(6-1-1) Utilization Unit 2

In the refrigerant circuit 11, the utilization-side heat exchanger 13 belongs to the utilization unit 2. In addition, a utilization-side fan 14 is mounted in the utilization unit 2. The utilization-side fan 14 generates an air flow to the utilization-side heat exchanger 13.

A utilization-side communicator 35 and a utilization-side microcomputer 41 are mounted in the utilization unit 2. The utilization-side communicator 35 is connected to the utilization-side microcomputer 41.

The utilization-side communicator 35 is used by the utilization unit 2 to communicate with the heat source unit 3. The utilization-side microcomputer 41 is supplied with a control voltage even during a standby state in which the air conditioner 1 is not operating. Thus, the utilization-side microcomputer 41 is constantly activated.

(6-1-2) Heat Source Unit 3

In the refrigerant circuit 11, the compressor 100, the four-way switching valve 16, the heat-source-side heat exchanger 17, and the expansion valve 18 belong to the heat source unit 3. In addition, a heat-source-side fan 19 is mounted in the heat source unit 3. The heat-source-side fan 19 generates an air flow to the heat-source-side heat exchanger 17.

In addition, a power conversion device 30, a heat-source-side communicator 36, and a heat-source-side microcomputer 42 are mounted in the heat source unit 3. The power conversion device 30 and the heat-source-side communicator 36 are connected to the heat-source-side microcomputer 42.

The power conversion device 30 is a circuit for driving a motor 70 of the compressor 100. The heat-source-side communicator 36 is used by the heat source unit 3 to communicate with the utilization unit 2. The heat-source-side microcomputer 42 controls the motor 70 of the compressor 100 via the power conversion device 30 and also controls other devices in the heat source unit 3 (for example, the heat-source-side fan 19).

FIG. 4 is a circuit block diagram of the power conversion device 30. In FIG. 4 , the motor 70 of the compressor 100 is a three-phase brushless DC motor and includes a stator 72 and a rotor 71. The stator 72 includes star-connected phase windings Lu, Lv, and Lw of a U-phase, a V-phase, and a W-phase. One ends of the phase windings Lu, Lv, and Lw are respectively connected to phase winding terminals TU, TV, and TW of wiring lines of the U-phase, the V-phase, and the W-phase extending from an inverter 25. The other ends of the phase windings Lu, Lv, and Lw are connected to each other at a terminal TN. These phase windings Lu, Lv, and Lw each generate an induced voltage in accordance with the rotation speed and position of the rotor 71 when the rotor 71 rotates.

The rotor 71 includes a permanent magnet with a plurality of poles, the N-pole and the S-pole, and rotates about a rotation axis with respect to the stator 72.

(6-2) Configuration of Power Conversion Device 30

The power conversion device 30 is mounted in the heat source unit 3, as illustrated in FIG. 3 . The power conversion device 30 is constituted by a power source circuit 20, the inverter 25, a gate driving circuit 26, and the heat-source-side microcomputer 42, as illustrated in FIG. 4 . The power source circuit 20 is constituted by a rectifier circuit 21 and a capacitor 22.

(6-2-1) Rectifier Circuit 21

The rectifier circuit 21 has a bridge structure made up of four diodes D1 a, D1 b, D2 a, and D2 b. Specifically, the diodes D1 a and D1 b are connected in series to each other, and the diodes D2 a and D2 b are connected in series to each other. The cathode terminals of the diodes D1 a and D2 a are connected to a plus-side terminal of the capacitor 22 and function as a positive-side output terminal of the rectifier circuit 21. The anode terminals of the diodes D1 b and D2 b are connected to a minus-side terminal of the capacitor 22 and function as a negative-side output terminal of the rectifier circuit 21.

A node between the diode D1 a and the diode D1 b is connected to one pole of an alternating-current (AC) power source 90. A node between the diode D2 a and the diode D2 b is connected to the other pole of the AC power source 90. The rectifier circuit 21 rectifies an AC voltage output from the AC power source 90 to generate a direct-current (DC) voltage, and supplies the DC voltage to the capacitor 22.

(6-2-2) Capacitor 22

The capacitor 22 has one end connected to the positive-side output terminal of the rectifier circuit 21 and has the other end connected to the negative-side output terminal of the rectifier circuit 21. The capacitor 22 is a small-capacitance capacitor that does not have a large capacitance for smoothing a voltage rectified by the rectifier circuit 21. Hereinafter, a voltage between the terminals of the capacitor 22 will be referred to as a DC bus voltage Vdc for the convenience of description.

The DC bus voltage Vdc is applied to the inverter 25 connected to the output side of the capacitor 22. In other words, the rectifier circuit 21 and the capacitor 22 constitute the power source circuit 20 for the inverter 25.

The capacitor 22 smooths voltage variation caused by switching in the inverter 25. In this embodiment, a film capacitor is adopted as the capacitor 22.

(6-2-3) Voltage Detector 23

A voltage detector 23 is connected to the output side of the capacitor 22 and is for detecting the value of a voltage across the capacitor 22, that is, the DC bus voltage Vdc. The voltage detector 23 is configured such that, for example, two resistors connected in series to each other are connected in parallel to the capacitor 22 and the DC bus voltage Vdc is divided. A voltage value at a node between the two resistors i s input to the heat-source-side microcomputer 42.

(6-2-4) Current Detector 24

A current detector 24 is connected between the capacitor 22 and the inverter 25 and to the negative-side output terminal side of the capacitor 22. The current detector 24 detects a motor current that flows through the motor 70 after the motor 70 is activated, as a total value of currents of the three phases.

The current detector 24 may be constituted by, for example, an amplifier circuit including a shunt resistor and an operational amplifier that amplifies a voltage across the shunt resistor. The motor current detected by the current detector 24 is input to the heat-source-side microcomputer 42.

(6-2-5) Inverter 25

In the inverter 25, three pairs of upper and lower arms respectively corresponding to the phase windings Lu, Lv, and Lw of the U-phase, the V-phase, and the W-phase of the motor 70 are connected in parallel to each other and connected to the output side of the capacitor 22.

In FIG. 4 , the inverter 25 includes a plurality of insulated gate bipolar transistors (IGBTs, hereinafter simply referred to as transistors) Q3 a, Q3 b, Q4 a, Q4 b, Q5 a, and Q5 b, and a plurality of free wheeling diodes D3 a, D3 b, D4 a, D4 b, D5 a, and D5 b.

The transistors Q3 a and Q3 b are connected in series to each other, the transistors Q4 a and Q4 b are connected in series to each other, and the transistors Q5 a and Q5 b are connected in series to each other, to constitute respective upper and lower arms and to form nodes NU, NV, and NW, from which output lines extend toward the phase windings Lu, Lv, and Lw of the corresponding phases.

The diodes D3 a to D5 b are connected in parallel to the respective transistors Q3 a to Q5 b such that the collector terminal of the transistor is connected to the cathode terminal of the diode and that the emitter terminal of the transistor is connected to the anode terminal of the diode. The transistor and the diode connected in parallel to each other constitute a switching element.

The inverter 25 generates driving voltages SU, SV, and SW for driving the motor 70 in response to ON and OFF of the transistors Q3 a to Q5 b at the timing when the DC bus voltage Vdc is applied from the capacitor 22 and when an instruction is provided from the gate driving circuit 26. The driving voltages SU, SV, and SW are respectively output from the node NU between the transistors Q3 a and Q3 b, the node NV between the transistors Q4 a and Q4 b, and the node NW between the transistors Q5 a and Q5 b to the phase windings Lu, Lv, and Lw of the motor 70.

(6-2-6) Gate Driving Circuit 26

The gate driving circuit 26 changes the ON and OFF states of the transistors Q3 a to Q5 b of the inverter 25 on the basis of instruction voltages from the heat-source-side microcomputer 42. Specifically, the gate driving circuit 26 generates gate control voltages Gu, Gx, Gv, Gy, Gw, and Gz to be applied to the gates of the respective transistors Q3 a to Q5 b so that the pulsed driving voltages SU, SV, and SW having a duty determined by the heat-source-side microcomputer 42 are output from the inverter 25 to the motor 70. The generated gate control voltages Gu, Gx, Gv, Gy, Gw, and Gz are applied to the gate terminals of the respective transistors Q3 a to Q5 b.

(6-2-7) Heat-Source-Side Microcomputer 42

The heat-source-side microcomputer 42 is connected to the voltage detector 23, the current detector 24, and the gate driving circuit 26. In this embodiment, the heat-source-side microcomputer 42 causes the motor 70 to be driven by using a rotor position sensorless method. The driving method is not limited to the rotor position sensorless method, and a sensor method may be used.

The rotor position sensorless method is a method for performing driving by estimating the position and rotation rate of the rotor, performing PI control on the rotation rate, performing PI control on a motor current, and the like, by using various parameters indicating the characteristics of the motor 70, a detection result of the voltage detector 23 after the motor 70 is activated, a detection result of the current detector 24, and a predetermined formula model about control of the motor 70, and the like. The various parameters indicating the characteristics of the motor 70 include a winding resistance, an inductance component, an induced voltage, and the number of poles of the motor 70 that is used. For details of rotor position sensorless control, see patent literatures (for example, Japanese Unexamined Patent Application Publication No. 2013-17289).

(6-3) Features of First Embodiment

(6-3-1)

In the air conditioner 1 that uses a refrigerant mixture containing at least 1,2-difluoroethylene, the rotation rate of the motor 70 can be changed via the power conversion device 30 as necessary. In other words, the motor rotation rate of the compressor 100 can be changed in accordance with an air conditioning load, and thus a high annual performance factor (APF) can be achieved.

(6-3-2)

An electrolytic capacitor is not required on the output side of the rectifier circuit 21, and thus an increase in the size and cost of the circuit is suppressed.

(6-4) Modification Example of First Embodiment

FIG. 5 is a circuit block diagram of a power conversion device 130 according to a modification example of the first embodiment. In FIG. 5 , this modification example is different from the first embodiment in that a rectifier circuit 121 for three phases is adopted instead of the rectifier circuit 21 for a single phase, to support a three-phase AC power source 190 instead of the single-phase AC power source 90.

The rectifier circuit 121 has a bridge structure made up of six diodes D0 a, D0 b, D1 a, D1 b, D2 a, and D2 b. Specifically, the diodes D0 a and D0 b are connected in series to each other, the diodes D1 a and D1 b are connected in series to each other, and the diodes D2 a and D2 b are connected in series to each other.

The cathode terminals of the diodes D0 a, D1 a, and D2 a are connected to the plus-side terminal of the capacitor 22 and function as a positive-side output terminal of the rectifier circuit 121. The anode terminals of the diodes D0 b, D1 b, and D2 b are connected to the minus-side terminal of the capacitor 22 and function as a negative-side output terminal of the rectifier circuit 121.

A node between the diode D0 a and the diode D0 b is connected to an R-phase output side of the AC power source 190. A node between the diode D1 a and the diode D1 b is connected to an S-phase output side of the AC power source 190. A node between the diode D2 a and the diode D2 b is connected to a T-phase output side of the AC power source 190. The rectifier circuit 121 rectifies an AC voltage output from the AC power source 190 to generate a DC voltage, and supplies the DC voltage to the capacitor 22.

Other than that, the configuration is similar to that of the above-described embodiment, and thus the description thereof is omitted.

(6-5) Features of Modification Example of First Embodiment

(6-5-1)

In the air conditioner 1 that uses a refrigerant mixture containing at least 1,2-difluoroethylene, the rotation rate of the motor 70 can be changed via the power conversion device 130 as necessary. In other words, the motor rotation rate of the compressor 100 can be changed in accordance with an air conditioning load, and thus a high annual performance factor (APF) can be achieved.

(6-5-2)

An electrolytic capacitor is not required on the output side of the rectifier circuit 121, and thus an increase in the size and cost of the circuit is suppressed.

(7) Second Embodiment

FIG. 6 is a circuit block diagram of a power conversion device 30B mounted in an air conditioner according to a second embodiment of the present disclosure.

(7-1) Configuration of Power Conversion Device 30B

In FIG. 6 , the power conversion device 30B is an indirect matrix converter. The difference from the power conversion device 30 according to the first embodiment in FIG. 17 is that a converter 27 is adopted instead of the rectifier circuit 21 and that a gate driving circuit 28 and a reactor 33 are newly added. Other than that, the configuration is similar to that of the first embodiment.

Here, a description will be given of the converter 27, the gate driving circuit 28, and the reactor 33, and a description of the other components is omitted.

(7-1-1) Converter 27

In FIG. 6 , the converter 27 includes a plurality of insulated gate bipolar transistors (IGBTs, hereinafter simply referred to as transistors) Q1 a, Q1 b, Q2 a, and Q2 b, and a plurality of diodes D1 a, D1 b, D2 a, and D2 b.

The transistors Q1 a and Q1 b are connected in series to each other to constitute upper and lower arms, and a node formed accordingly is connected to one pole of the AC power source 90. The transistors Q2 a and Q2 b are connected in series to each other to constitute upper and lower arms, and a node formed accordingly is connected to the other pole of the AC power source 90.

The diodes D1 a to D2 b are connected in parallel to the respective transistors Q1 a to Q2 b such that the collector terminal of the transistor is connected to the cathode terminal of the diode and that the emitter terminal of the transistor is connected to the anode terminal of the diode. The transistor and the diode connected in parallel to each other constitute a switching element.

In the converter 27, the transistors Q1 a to Q2 b are turned ON and OFF at the timing when an instruction is provided from the gate driving circuit 28.

(7-1-2) Gate Driving Circuit 28

The gate driving circuit 28 changes the ON and OFF states of the transistors Q1 a to Q2 b of the converter 27 on the basis of instruction voltages from the heat-source-side microcomputer 42. Specifically, the gate driving circuit 28 generates pulsed gate control voltages Pq, Pr, Ps, and Pt having a duty determined by the heat-source-side microcomputer 42 so as to control a current flowing from the AC power source 90 toward the heat source to a predetermined value. The generated gate control voltages Pq, Pr, Ps, and Pt are applied to the gate terminals of the respective transistors Q1 a to Q2 b.

(7-1-3) Reactor 33

The reactor 33 is connected in series to the AC power source 90 between the AC power source 90 and the converter 27. Specifically, one end thereof is connected to one pole of the AC power source 90, and the other end thereof is connected to one input terminal of the converter 27.

(7-2) Operation

The heat-source-side microcomputer 42 turns ON/OFF the transistors Q1 a and Q1 b or the transistors Q2 a and Q2 b of the upper and lower arms of the converter 27 to short-circuit/open the transistors for a predetermined time, and controls a current to, for example, a substantially sinusoidal state, thereby improving a power factor of power source input and suppressing harmonic components.

In addition, the heat-source-side microcomputer 42 performs cooperative control between the converter and the inverter so as to control a short-circuit period on the basis of a duty ratio of a gate control voltage for controlling the inverter 25.

(7-3) Features of Second Embodiment

The air conditioner 1 is highly efficient and does not require an electrolytic capacitor on the output side of the converter 27, and thus an increase in the size and cost of the circuit is suppressed.

(7-4) Configuration of Power Conversion Device 130B According to Modification Example of Second Embodiment

FIG. 7 is a circuit block diagram of a power conversion device 130B according to a modification example of the second embodiment. In FIG. 7 , this modification example is different from the second embodiment in that a converter 127 for three phases is adopted instead of the converter 27 for a single phase, to support the three-phase AC power source 190 instead of the single-phase AC power source 90. In accordance with the change from the converter 27 for a single phase to the converter 127 for three phases, a gate driving circuit 128 is adopted instead of the gate driving circuit 28. Furthermore, reactors 33 are connected between the converter 127 and the output sides of the respective phases. Capacitors are connected between input-side terminals of the reactors 33. Alternatively, these capacitors may be removed.

(7-4-1) Converter 127

The converter 127 includes a plurality of insulated gate bipolar transistors (IGBTs, hereinafter simply referred to as transistors) Q0 a, Q0 b, Q1 a, Q1 b, Q2 a, and Q2 b, and a plurality of diodes D0 a, D0 b, D1 a, D1 b, D2 a, and D2 b.

The transistors Q0 a and Q0 b are connected in series to each other to constitute upper and lower arms, and a node formed accordingly is connected to the R-phase output side of the AC power source 190. The transistors Q1 a and Q1 b are connected in series to each other to constitute upper and lower arms, and a node formed accordingly is connected to the S-phase output side of the AC power source 190. The transistors Q2 a and Q2 b are connected in series to each other to constitute upper and lower arms, and a node formed accordingly is connected to the T-phase output side of the AC power source 190.

The diodes D0 a to D2 b are connected in parallel to the respective transistors Q0 a to Q2 b such that the collector terminal of the transistor is connected to the cathode terminal of the diode and that the emitter terminal of the transistor is connected to the anode terminal of the diode. The transistor and the diode connected in parallel to each other constitute a switching element.

In the converter 127, the transistors Q0 a to Q2 b are turned ON and OFF at the timing when an instruction is provided from the gate driving circuit 128.

(7-4-2) Gate Driving Circuit 128

The gate driving circuit 128 changes the ON and OFF states of the transistors Q0 a to Q2 b of the converter 127 on the basis of instruction voltages from the heat-source-side microcomputer 42. Specifically, the gate driving circuit 128 generates pulsed gate control voltages Po, Pp, Pq, Pr, Ps, and Pt having a duty determined by the heat-source-side microcomputer 42 so as to control a current flowing from the AC power source 190 toward the heat source to a predetermined value. The generated gate control voltages Po, Pp, Pq, Pr, Ps, and Pt are applied to the gate terminals of the respective transistors Q0 a to Q2 b.

(7-5) Features of Modification Example of Second Embodiment

The air conditioner 1 is highly efficient and does not require an electrolytic capacitor on the output side of the converter 127, and thus an increase in the size and cost of the circuit is suppressed.

(8) Third Embodiment

FIG. 8 is a circuit block diagram of a power conversion device 30C mounted in an air conditioner according to a third embodiment of the present disclosure.

(8-1) Configuration of Power Conversion Device 30C According to Third Embodiment

In FIG. 8 , the power conversion device 30C is a matrix converter 29.

(8-1-1) Configuration of Matrix Converter 29

The matrix converter 29 is configured by connecting bidirectional switches S1 a, S2 a, and S3 a to one end of input from the AC power source 90 and connecting bidirectional switches S1 b, S2 b, and S3 b to the other end.

An intermediate terminal between the bidirectional switch S1 a and the bidirectional switch S1 b connected in series to each other is connected to one end of the U-phase winding Lu among the three-phase windings of the motor 70. An intermediate terminal between the bidirectional switch S2 a and the bidirectional switch S2 b connected in series to each other is connected to one end of the V-phase winding Lv among the three-phase windings of the motor 70. An intermediate terminal between the bidirectional switch S3 and the bidirectional switch S3 b connected in series to each other is connected to one end of the W-phase winding Lw among the three-phase windings of the motor 70.

AC power input from the AC power source 90 is switched by the bidirectional switches S1 a to S3 b and is converted into AC having a predetermined frequency, thereby being capable of driving the motor 70.

(8-1-2) Configuration of Bidirectional Switch

FIG. 9 is a circuit diagram conceptionally illustrating a bidirectional switch. In FIG. 9 , the bidirectional switch includes transistors Q61 and Q62, diodes D61 and D62, and terminals Ta and Tb. The transistors Q61 and Q62 are insulated gate bipolar transistors (IGBTs).

The transistor Q61 has an emitter E connected to the terminal Ta, and a collector C connected to the terminal Tb via the diode D61. The collector C is connected to the cathode of the diode D61.

The transistor Q62 has an emitter E connected to the terminal Tb, and a collector C connected to the terminal Ta via the diode D62. The collector C is connected to the cathode of the diode D62. The terminal Ta is connected to an input side, and the terminal Tb is connected to an output side.

Turning ON of the transistor Q61 and turning OFF of the transistor Q62 enables a current to flow from the terminal Tb to the terminal Ta via the diode D61 and the transistor Q61 in this order. At this time, a flow of a current from the terminal Ta to the terminal Tb (backflow) is prevented by the diode D61.

On the other hand, turning OFF of the transistor Q61 and turning ON of the transistor Q62 enables a current to flow from the terminal Ta to the terminal Tb via the diode D62 and the transistor Q62 in this order. At this time, a flow of a current from the terminal Tb to the terminal Ta (backflow) is prevented by the diode D62.

(8-2) Operation

FIG. 10 is a circuit diagram illustrating an example of a current direction in the matrix converter 29. FIG. 10 illustrates an example of a path of a current that flows from the AC power source 90 via the matrix converter 29 to the motor 70. The current flows from one pole of the AC power source 90 to the other pole of the AC power source 90 via the bidirectional switch S1 a, the U-phase winding Lu which is one of the three-phase windings of the motor 70, the W-phase winding Lw, and the bidirectional switch S3 b. Accordingly, power is supplied to the motor 70 and the motor 70 is driven.

FIG. 11 is a circuit diagram illustrating an example of another current direction in the matrix converter 29. In FIG. 11 , a current flows from one pole of the AC power source 90 to the other pole of the AC power source 90 via the bidirectional switch S3 a, the W-phase winding Lw which is one of the three-phase windings of the motor 70, the U-phase winding Lu, and the bidirectional switch S1 b. Accordingly, power is supplied to the motor 70 and the motor 70 is driven.

(8-3) Features of Third Embodiment

The air conditioner 1 is highly efficient and does not require an electrolytic capacitor on the output side of the matrix converter 29, and thus an increase in the size and cost of the circuit is suppressed.

(8-4) Configuration of Power Conversion Device 130C According to Modification Example of Third Embodiment

FIG. 12 is a circuit block diagram of a power conversion device 130C according to a modification example of the third embodiment. In FIG. 12 , this modification example is different from the third embodiment in that a matrix converter 129 for three phases is adopted instead of the matrix converter 29 for a single phase, to support the three-phase AC power source 190 instead of the single-phase AC power source 90.

(8-4-1) Configuration of Matrix Converter 129

It is also a difference that a gate driving circuit 131 is adopted instead of a gate driving circuit 31 in accordance with the change from the matrix converter 29 for a single phase to the matrix converter 129 for three phases. Furthermore, reactors L1, L2, and L3 are connected between the matrix converter 129 and the output sides of the respective phases.

Predetermined three-phase AC voltages obtained through conversion by bidirectional switches S1 a to S3 c are supplied to the motor 70 via the phase winding terminals TU, TV, and TW. The reactors L1, L2, and L3 are connected to respective input terminals of matrix converter 129. Capacitors C1, C2, and C3 are connected to each other at one ends thereof, and the other ends thereof are connected to output terminals of matrix converter 129.

In the power conversion device 130C, the reactors L1, L2, and L3 are short-circuited via the matrix converter 129, and thereby the energy supplied from the three-phase AC power source 190 can be accumulated in the reactors L1, L2, and L3 and the voltages across the capacitors C1, C2, and C3 can be increased. Accordingly, a voltage utilization rate of 1 or more can be achieved.

At this time, voltage-type three-phase AC voltages Vr, Vs, and Vt are input to the input terminals of the matrix converter 129, and current-type three-phase AC voltages Vu, Vv, and Vw are output from the output terminals.

In addition, the capacitors C1, C2, and C3 constitute LC filters with the reactors L1, L2, and L3, respectively. Thus, high-frequency components included in voltages output to the output terminals can be reduced, and torque pulsation components and noise generated in the motor 70 can be reduced.

Furthermore, compared with an AC-AC conversion circuit including a rectifier circuit and an inverter, the number of switching elements is smaller, and the loss that occurs in the power conversion device 130C can be reduced.

(8-4-2) Configuration of Clamp Circuit 133

In the power conversion device 130, a clamp circuit 133 is connected between the input terminals and the output terminals. Thus, a surge voltage generated between the input terminals and the output terminals of the matrix converter 129 through switching of the bidirectional switches S1 a to S3 c can be absorbed by a capacitor in the clamp circuit 133 (see FIG. 11 ).

FIG. 13 is a circuit diagram of the clamp circuit 133. In FIG. 13 , the clamp circuit 133 has diodes D31 a to D36 b, a capacitor C37, and terminals 135 to 140.

The anode of the diode D31 a and the cathode of the diode D31 b are connected to the terminal 135. The anode of the diode D32 a and the cathode of the diode D32 b are connected to the terminal 136. The anode of the diode D33 a and the cathode of the diode D33 b are connected to the terminal 137.

The cathodes of the diodes D31 a, D32 a, and D33 a are connected to one end of the capacitor C37. The anodes of the diodes D31 b, D32 b, and D33 b are connected to the other end of the capacitor C37.

The anode of the diode D34 a and the cathode of the diode D34 b are connected to the terminal 138. The anode of the diode D35 a and the cathode of the diode D35 b are connected to the terminal 139. The anode of the diode D36 a and the cathode of the diode D36 b are connected to the terminal 140.

The cathodes of the diodes D34 a, D35 a, and D36 a are connected to the one end of the capacitor C37. The anodes of the diodes D34 b, D35 b, and D36 b are connected to the other end of the capacitor C37.

The terminals 135, 136, and 137 are connected to the input side of the matrix converter 129, and the terminals 138, 139, and 140 are connected to the output side of the matrix converter 129. Because the clamp circuit 133 is connected between the input terminals and the output terminals, a surge voltage generated between the input terminals and the output terminals of the matrix converter 129 through switching of the bidirectional switches S1 a to S3 b can be absorbed by the capacitor C37 in the clamp circuit 133.

As described above, the power conversion device 130C is capable of supplying a voltage larger than a power source voltage to the motor 70. Thus, even if the current flowing through the power conversion device 130C and the motor 70 is small, a predetermined motor output can be obtained, in other words, only a small current is used. Accordingly, the loss that occurs in the power conversion device 130C and the motor 70 can be reduced.

(8-5) Features of Modification Example of Third Embodiment

The air conditioner 1 is highly efficient and does not require an electrolytic capacitor on the output side of the matrix converter 129, and thus an increase in the size and cost of the circuit is suppressed.

(9) Others

(9-1)

As the compressor 100 of the air conditioner 1, any one of a scroll compressor, a rotary compressor, a turbo compressor, and a screw compressor is adopted.

(9-2)

The motor 70 of the compressor 100 is a permanent magnet synchronous motor having the rotor 71 including a permanent magnet.

Embodiments of the present disclosure have been described above. It is to be understood that various changes of the embodiments and details are possible without deviating from the gist and scope of the present disclosure described in the claims.

REFERENCE SIGNS LIST

-   -   1: air conditioner     -   21: rectifier circuit     -   22: capacitor     -   25: inverter     -   27: converter     -   30: power conversion device     -   30B: indirect matrix converter (power conversion device)     -   30C: matrix converter (power conversion device)     -   70: motor     -   71: rotor     -   100: compressor     -   130: power conversion device     -   130B: indirect matrix converter (power conversion device)     -   130C: matrix converter (power conversion device)

CITATION LIST Patent Literature

-   PTL 1: Japanese Unexamined Patent Application Publication No.     2013-124848 

1. An air conditioner comprising: a compressor (100) that compresses a refrigerant mixture containing at least 1,2-difluoroethylene; a motor (70) that drives the compressor (100); and a power conversion device (30, 130, 30B, 130B, 30C, 130C) that is connected between an alternating-current (AC) power source and the motor (70), that has a switching element, and that controls the switching element such that an output of the motor (70) becomes a target value.
 2. The air conditioner according to claim 1, wherein the power conversion device (30, 130) includes a rectifier circuit (21) that rectifies an AC voltage of the AC power source, and a capacitor (22) that is connected in parallel to an output side of the rectifier circuit (21) and smooths voltage variation caused by switching in the power conversion device (30).
 3. The air conditioner according to claim 1, wherein the AC power source is a single-phase power source.
 4. The air conditioner according to claim 1, wherein the AC power source is a three-phase power source.
 5. The air conditioner according to claim 1, wherein the power conversion device (30B, 130B) is an indirect matrix converter including a converter (27) that receives an AC voltage of the AC power source and converts the AC voltage into a direct-current (DC) voltage, and an inverter (25) that converts the DC voltage into an AC voltage and supplies the AC voltage to the motor.
 6. The air conditioner according to claim 1, wherein the power conversion device (30C, 130C) is a matrix converter that directly converts an AC voltage of the AC power source into an AC voltage having a predetermined frequency and supplies the AC voltage having the predetermined frequency to the motor.
 7. The air conditioner according to claim 1, wherein the compressor (100) is any one of a scroll compressor, a rotary compressor, a turbo compressor, and a screw compressor.
 8. The air conditioner according to claim 1, wherein the motor (70) is a permanent magnet synchronous motor having a rotor (71) including a permanent magnet.
 9. The air conditioner according to claim 1, wherein the refrigerant comprises trans-1,2-difluoroethylene (HFO-1132(E)), difluoromethane (R32), and 2,3,3,3-tetrafluoro-1-propene (R1234yf), wherein when the mass % of HFO-1132(E), R32, and R1234yf based on their sum in the refrigerant is respectively represented by x, y, and z, coordinates (x,y,z) in a ternary composition diagram in which the sum of HFO-1132(E), R32, and R1234yf is 100 mass % are within the range of a figure surrounded by line segments IJ, JN, NE, and EI that connect the following 4 points: point I (72.0, 0.0, 28.0), point J (48.5, 18.3, 33.2), point N (27.7, 18.2, 54.1), and point E (58.3, 0.0, 41.7), or on these line segments (excluding the points on the line segment EI; the line segment IJ is represented by coordinates (0.0236y²−1.7616y+72.0, y, −0.0236y²+0.7616y+28.0); the line segment NE is represented by coordinates (0.012y²−1.9003y+58.3, y, −0.012y²+0.9003y+41.7); and the line segments JN and EI are straight lines.
 10. The air conditioner according to claim 1, wherein the refrigerant comprises HFO-1132(E), R32, and R1234yf, wherein when the mass % of HFO-1132(E), R32, and R1234yf based on their sum in the refrigerant is respectively represented by x, y, and z, coordinates (x,y,z) in a ternary composition diagram in which the sum of HFO-1132(E), R32, and R1234yf is 100 mass % are within the range of a figure surrounded by line segments MM′, M′N, NV, VG, and GM that connect the following 5 points: point M (52.6, 0.0, 47.4), point M′ (39.2, 5.0, 55.8), point N (27.7, 18.2, 54.1), point V (11.0, 18.1, 70.9), and point G (39.6, 0.0, 60.4), or on these line segments (excluding the points on the line segment GM); the line segment MM′ is represented by coordinates (0.132y²−3.34y+52.6, y, −0.132y²+2.34y+47.4); the line segment M′N is represented by coordinates (0.0596y²−2.2541y+48.98, y, −0.0596y²+1.2541y+51.02); the line segment VG is represented by coordinates (0.0123y²−1.8033y+39.6, y, −0.0123y²+0.8033y+60.4); and the line segments NV and GM are straight lines.
 11. The air conditioner according to claim 1, wherein the refrigerant comprises HFO-1132(E), R32, and R1234yf, wherein when the mass % of HFO-1132(E), R32, and R1234yf based on their sum in the refrigerant is respectively represented by x, y and z, coordinates (x,y,z) in a ternary composition diagram in which the sum of HFO-1132(E), R32, and R1234yf is 100 mass % are within the range of a figure surrounded by line segments ON, NU, and UO that connect the following 3 points: point O (22.6, 36.8, 40.6), point N (27.7, 18.2, 54.1), and point U (3.9, 36.7, 59.4), or on these line segments; the line segment ON is represented by coordinates (0.0072y²−0.6701y+37.512, y, −0.0072y²−0.3299y+62.488); the line segment NU is represented by coordinates (0.0083y²−1.7403y+56.635, y, −0.0083y²+0.7403y+43.365); and the line segment UO is a straight line.
 12. The air conditioner according to claim 1, wherein the refrigerant comprises HFO-1132(E), R32, and R1234yf, wherein when the mass % of HFO-1132(E), R32, and R1234yf based on their sum in the refrigerant is respectively represented by x, y, and z, coordinates (x,y,z) in a ternary composition diagram in which the sum of HFO-1132(E), R32, and R1234yf is 100 mass % are within the range of a figure surrounded by line segments QR, RT, TL, LK, and KQ that connect the following 5 points: point Q (44.6, 23.0, 32.4), point R (25.5, 36.8, 37.7), point T (8.6, 51.6, 39.8), point L (28.9, 51.7, 19.4), and point K (35.6, 36.8, 27.6), or on these line segments; the line segment QR is represented by coordinates (0.0099y²−1.975y+84.765, y, −0.0099y²+0.975y+15.235); the line segment RT is represented by coordinates (0.0082y²−1.8683y+83.126, y, −0.0082y²+0.8683y+16.874); the line segment LK is represented by coordinates (0.0049y²−0.8842y+61.488, y, −0.0049y²−0.1158y+38.512); the line segment KQ is represented by coordinates (0.0095y²−1.2222y+67.676, y, −0.0095y²+0.2222y+32.324); and the line segment TL is a straight line.
 13. The air conditioner according to claim 1, wherein the refrigerant comprises HFO-1132(E), R32, and R1234yf, wherein when the mass % of HFO-1132(E), R32, and R1234yf based on their sum in the refrigerant is respectively represented by x, y, and z, coordinates (x,y,z) in a ternary composition diagram in which the sum of HFO-1132(E), R32, and R1234yf is 100 mass % are within the range of a figure surrounded by line segments PS, ST, and TP that connect the following 3 points: point P (20.5, 51.7, 27.8), point S (21.9, 39.7, 38.4), and point T (8.6, 51.6, 39.8), or on these line segments; the line segment PS is represented by coordinates (0.0064y²−0.7103y+40.1, y, −0.0064y²−0.2897y+59.9); the line segment ST is represented by coordinates (0.0082y²−1.8683y+83.126, y, −0.0082y²+0.8683y+16.874); and the line segment TP is a straight line. 